And onto the wiring.

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
The car is a 99 mk3 body AHU with no immobilizer and I got my engine and harness pulled finally this evening, I have the harness loom cut back as well as starting to remove the not used portions.

I have a few questions though. After I get my harness separated, is there a way to eliminate the fuse/relay center that used to reside under the dash? It would be awesome to free up all that space in the cramped package of my samurai.

Any tips for a tdi swap virgin are welcomed for sure, I have completed other swaps in the past (302 into RBV, fummins, etcq) , but that was a whole different ball game compared to this.I have been researching for months, and I am very comfortable with wiring but any infor is helpfull.
As always, thanks ahead of time guys.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
yes!....the last mkiii swap harness i built i used the snap together relay and fuse holders already present in your harness.... you'll end up with two relays and two fuses that all snap together in a neat rectangle :).... another option is to scavenge the underhood relay box from an mkiv ... most any mkiv will have one ... it has enough fuse spots and relay spots for engine management ...you will also need to procure the mounting bracket as well (a few spot welds) and some wiring pigtails/relay bases ...
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
Thanls jimbote, I was hoping you were going to chime in. I will be working on it tonight again so im sure ill run into more questions.
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
This is what I got it whittled down to. 2 fuses, glow plug relay and power supply relay
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
Thats more the size I was hoping for, I havent looked into the wiring for relay 109, is it just your regular 4 pin relay? I need to keep it all as weatherproof as possible being an offroad rig.
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
yes, its a 4 leg relay. Back when I wheeled a samurai I would have just stuck that in a ziplock bag and tied it off good.
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
Unfortunately I didnt get time to work on it tonight, ill get the dash pulled tommorrow to get the complete harness andthen it will truly be onto the wiring. Again, any tips/links you guys provide will be greatly appreciated.
 

frozenplum4

Member
Joined
Mar 4, 2013
Location
san antonio
TDI
none for now
Wait, that can't be all of the wiring you end up with? Is this some of the engine wiring left?

That's the one thing that I've been worried about and seeing this is pretty encouraging
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
Wait, that can't be all of the wiring you end up with? Is this some of the engine wiring left?

That's the one thing that I've been worried about and seeing this is pretty encouraging
That and the sensors for the engine but they are already wired up to the ECU. I have one ground, one 12v constant and one switched 12v to hook up. Few other things like brake input and tach I haven't addressed yet.
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
So tonight I got the dash and harness pulled, strippedthe harness down to what I believe to be minimal, hopefully I never got rid of anything I need..
I have the following connectors/components
-large round engine connector
-black/brown connectors on round connector bracket
-crank sensor connector
-relay 180
-IP connector
-pedal connector
-brake/clutch switch connectors
And with that, I have some questions/extra wires
I am calling the "branch" of the harness that leads to the pcm, the pcm from here out. Im not looking to be spoon fed, just looking for re assurance im on the right track but im not about to turn down any info on what I have left over.

Single wire- black red, heads to pcm

4 pin black-all wires head to the pcm

Multi pin green-green/blue and orange grey head to the pcm

Clear connector-multiple black yellows from pcm into splice turns to fat blue/red, brown/white and white/blue go to the round engine connector, black/violet-black green and black head to the pcm

Yellow and yellow red to round connector, blue/green to pcm and blue/black goes to the pcm and round connectors
I also have a black yellow coming from the pcm and a black yellow comong from the fan control, is it possible I knicked the wire cutting the harness apart? I dont remember cutting the wire.
I have a brown/blacl from the pcm im assuming ground?
I have a light blue wire out of the pcm as well
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
Thank you, I thought I had looked everywhere for a pinout but was told they didnt exsist. Thanks again, this makes l8fe a whole lot easier rather than tracing track diagrams!
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
So I got it whittled down to the following and am looking for some clarification.

Pin 39-alternator load signal- I am undecided what alternator im using for my swap, so if I use the vw alternator it will obviously just go to the terminal in the connector, but if I choose to run a gm alternator or otherwise do I just get rid of this wire or does the pcm want to see something here?

Pin 44-brake lights- its my understanding I will get a flashing glow plug light if I dont run this, does the pcm want to see a change from no V to V or can this be ran to 12v and its overwith? Or do I tie it into the other brake switch?

Pin 28-A/C relay- Does this bump the idle up when it sees the request for ac? If so, can this be used as a type of high idle? If so, is it + or -?

Pin 42-relay 109- pin 85 of relay 109
Large blue/red wire to pin 87 of relay 109
Pin 86 to ground and pin 30 to constant 12v source

Pin 38-ign from key- obviously goes to ignition

Pin 42-vss cluster, pin 7- Is this one vss in? I need to do some more searching on what I need to setup as I dont have a vss in the samurai but am hoping to use something similar to the mod for a 1.6 16v swap for those familiar

Pin 2-tach- assuming this will run my tach, from what I gather, since im going from a 4 cyl to a 4cyl I shouldnt need to do much work.

Pin 66-MIL- Ive heard I need to do some trickery with a transistor and resistor, is there truth to this?

Pin 48-GP light- same questions as MIL

Pin 61-OBD connector pin 7, kline- just run to pin 7 or obd2 connector

And the three wires for cruise(blue/grey, red, black/white) now the 3 wires are straight forward, found 4th wire on stalk will go to 12v accessory/ignition

I also ended up with 4 wires going to the round engine connector as well, they are:
Yellow/red(pin 3)- I believe to be coolant temp
Yellow(pin 2)-havent looked
Brown/white(pin 4) havent looking
White/blue (no pin number but towards center of pin5) havent looked
 
Last edited:

Alchemist

Veteran Member
Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
Here are a few steps closer to completion.

So I got it whittled down to the following and am looking for some clarification.

Pin 39-alternator load signal- I am undecided what alternator im using for my swap, so if I use the vw alternator it will obviously just go to the terminal in the connector, but if I choose to run a gm alternator or otherwise do I just get rid of this wire or does the pcm want to see something here? The ECM is looking for regulator output which indicates alternator loading. It will set a DTC and light the MIL if not present.

Pin 44-brake lights- its my understanding I will get a flashing glow plug light if I dont run this, does the pcm want to see a change from no V to V or can this be ran to 12v and its overwith? Or do I tie it into the other brake switch? This line is grounded through the brake lights and goes to +12 when the brakes are on. This arrangement allows the ECU to monitor the brake lights and flash the GP light if the brake light bulbs burn out. The ECU also needs to see a ground on Pin 20 White/Yellow or it will inhibit throttle. This needs to have the ground lifted with brakes on to disable cruise control.

Pin 28-A/C relay- Does this bump the idle up when it sees the request for ac? If so, can this be used as a type of high idle? If so, is it + or -?

Pin 42-relay 109- pin 85 of relay 109
Large blue/red wire to pin 87 of relay 109
Pin 86 to ground and pin 30 to constant 12v source Pins 30 and 86 connect to constant 12V, Pin 87 supplies the Blue/Red wire and ECU Pin 42 grounds 85 to activate the relay

Pin 38-ign from key- obviously goes to ignition

Pin 42-vss cluster, pin 7- Is this one vss in? I need to do some more searching on what I need to setup as I dont have a vss in the samurai but am hoping to use something similar to the mod for a 1.6 16v swap for those familiar This is an input to the ECU which is required to make cruise control work. If you are not going to connect the cruise wiring ignore it.

Pin 2-tach- assuming this will run my tach, from what I gather, since im going from a 4 cyl to a 4cyl I shouldnt need to do much work. This part should be PnP. The ECU puts out one pulse for each time a cylinder fires, same as a gasser.

Pin 66-MIL- Ive heard I need to do some trickery with a transistor and resistor, is there truth to this? It depends on how your instrument cluster is wired. Some clusters feed power to the bulbs and ground them to light. Others have the bulbs grounded and apply power to light. If the lights come on when the wire is grounded you are OK as is. If not, some magic is needed to convert the ECU ground signal to supply power.

Pin 48-GP light- same questions as MIL Same conditions and solution.

Pin 61-OBD connector pin 7, kline- just run to pin 7 or obd2 connector OBD2 Connector needs ground on Pins 4 and 5, constant power on Pin 16 and K line on Pin7.

And the three wires for cruise(blue/grey, red, black/white) now the 3 wires are straight forward, found 4th wire on stalk will go to 12v accessory/ignition The Black wire connects to Ignition 12V.

I also ended up with 4 wires going to the round engine connector as well, they are:
Yellow/red(pin 3)- I believe to be coolant temp
Yellow(pin 2)-havent looked
Brown/white(pin 4) havent looking
White/blue (no pin number but towards center of pin5) havent looked I will need to search my archives for this information, so it may take a while to come up with an answer. The rest should keep you out of mischief for an hour or two.
 

Alchemist

Veteran Member
Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
The rest of the story.

ECU Pin 28 Brown/Green output to AC relay to shut off AC

ECU Pin 37 Green/Grey AC on input signal to ECU that AC is on, may increase idle

Engine connector

Yellow/Red Engine temp sensor for gauge

Yellow F1 Oil Pressure Switch

Brown/White Ground

White/Blue VSS
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
Thanks everyone for the help, especially alchemist, I had another look at my diagram and it must be a misprint becasue it shows it my way for relay 109.

I got it running on the modified harness tonighy and its goinf goox. Onto ths mounts and the rest of the swap!
 

Hoff6282

Member
Joined
Mar 22, 2012
Location
Michigan
TDI
2000 Golf TDI (sold), 2002 Jetta Wagon TDI (sold), 1987 Vanagon Weekender mid-swap to AHU TDI
Hello all!
I know this thread has been quiet for a while, but I found it very helpful and thought I'd reach out to see if I could get some feedback. Thank you all for everything that has been posted so far and thanks in advance for any help.
I'm in the middle of swapping an AHU out of a 98 Jetta into my 87 Vanagon, and I am going the eTDI route and using the wiring harness and cluster out of the Jetta donor.
I was toying around with the idea of slapping the Jetta fuseblock underneath the rear bench right next to the ECU just so that I could limit the amount of hacking up of the factory harness, but after seeing that simplistic beauty that Rockwell posted and Jimbote spoke of, I think it makes way more sense to go that route.
I've been poring over wiring diagrams and pinout charts trying to make sure I've got it all straight in my head and am getting there, but I still had a few questions, especially with regards to the simplified relay/fuse plate that was pictured.
1) As far as I understand it, the two required relays are the Power Supply Relay and the Glow Plug Relay. On my diagrams, those are denoted as relays 109 and 103 respectively. In the picture, I'm seeing relay 180 and relay 53. As a sanity check, can someone confirm which relays are required for proper operation of an AHU eTDI?
2) With regards to the two fuses also shown on that plate, what are those tied to? I'm looking at a diagram that shows a 20A fuse linked to the GP relay, but what does that second 20A fuse go to?
3) For the pictured relay/fuse plate, are the base components that everything plugs into something I can just buy from an Auto parts store? Just 12V 4 Pin relay bases? Any special ratings I need to be aware of?
4) Last question (for now). As far as tying this new relay/fuse plate back to the Vanagon fuse panel, what is the best way to approach that? Looks like 109 needs tied into Direct Battery power and 103 needs tied to ignition on/switched power, but those two tracks run within the fuse panel circuit board itself. Should I anticipate having to open up the panel and solder onto a board, or are we just talking splicing into some existing wires?
I apologize if any of these questions are very novice, I'm still trying to harness my inner EE (mechanical engineering is my background).
Thank you in advance for any feedback, definitely very excited about this project and eager to get everything running!
Best Regards,
Scott
 

Alchemist

Veteran Member
Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
Hello all!
I know this thread has been quiet for a while, but I found it very helpful and thought I'd reach out to see if I could get some feedback. Thank you all for everything that has been posted so far and thanks in advance for any help.
I'm in the middle of swapping an AHU out of a 98 Jetta into my 87 Vanagon, and I am going the eTDI route and using the wiring harness and cluster out of the Jetta donor.
I was toying around with the idea of slapping the Jetta fuseblock underneath the rear bench right next to the ECU just so that I could limit the amount of hacking up of the factory harness, but after seeing that simplistic beauty that Rockwell posted and Jimbote spoke of, I think it makes way more sense to go that route.
I've been poring over wiring diagrams and pinout charts trying to make sure I've got it all straight in my head and am getting there, but I still had a few questions, especially with regards to the simplified relay/fuse plate that was pictured.
1) As far as I understand it, the two required relays are the Power Supply Relay and the Glow Plug Relay. On my diagrams, those are denoted as relays 109 and 103 respectively. In the picture, I'm seeing relay 180 and relay 53. As a sanity check, can someone confirm which relays are required for proper operation of an AHU eTDI? The early models used a 103 relay for glow plugs, but by 98 it should be a 180. A 53 relay, or any common automotive relay, will do the same job as a 109. The 109 has an internal connection of terminals 30 and 86, so if you make these connections externally you will have a 109 equivalent.
2) With regards to the two fuses also shown on that plate, what are those tied to? I'm looking at a diagram that shows a 20A fuse linked to the GP relay, but what does that second 20A fuse go to? The glow plug relay should have a 50 amp fuse in the supply line from the battery connected to Pin 2. It should also have switched power from the 109 relay connected to Pin 9.
3) For the pictured relay/fuse plate, are the base components that everything plugs into something I can just buy from an Auto parts store? Yes, except the glow plug relay which is a VW special. Just 12V 4 Pin relay bases? Any special ratings I need to be aware of? No
4) Last question (for now). As far as tying this new relay/fuse plate back to the Vanagon fuse panel, what is the best way to approach that? Looks like 109 needs tied into Direct Battery power and 103 needs tied to ignition on/switched power, but those two tracks run within the fuse panel circuit board itself. Should I anticipate having to open up the panel and solder onto a board, There is no board, just a jumble of metal strips. Opening one of those fuse panels is a mistake. or are we just talking splicing into some existing wires? All you need from the Vanagon electrical system is a heavy feed from the battery to the relays and switched ignition to the ECU. Switched ignition is typically a black wire.
I apologize if any of these questions are very novice, I'm still trying to harness my inner EE (mechanical engineering is my background).
Thank you in advance for any feedback, definitely very excited about this project and eager to get everything running!
Best Regards,
Scott
This should get you a bit closer. Let me know if I can do anything else for you.
 

Hoff6282

Member
Joined
Mar 22, 2012
Location
Michigan
TDI
2000 Golf TDI (sold), 2002 Jetta Wagon TDI (sold), 1987 Vanagon Weekender mid-swap to AHU TDI
Wow, thanks for the quick response, Alchemist, that was a huge help!

I will move forward with all of that in mind and will certainly circle back if I get stuck somewhere else along the way.

Best Regards,
 

Hoff6282

Member
Joined
Mar 22, 2012
Location
Michigan
TDI
2000 Golf TDI (sold), 2002 Jetta Wagon TDI (sold), 1987 Vanagon Weekender mid-swap to AHU TDI
Hello again!
It's been a while since I first asked some of these questions, and now I'm back into the wiring with more questions.
So, reading through this thread and with the advice I'd gotten from Alchemist, I put together a little diagram of what I "think" I need to wire the 3 key elements of this simplified setup (Relay 109, GP Relay, GP fuse) into the vanagon. See below:

Now, after trimming down my harness, below is what I'm looking at, similar to the images I saw earlier in the thread:

So, where I'm running into some questions is when I compare the diagram and what I think I'm supposed to wire vs. what used to be wired in the stock Jetta harness.
First off, the socket where I would have expected to have a 109 relay in the Jetta had a 53 relay, and coming out from the base are 4 wires, as opposed to 3. There was a relay 109 on the main fuse block in the Jetta, and if I pull that and compare it to the relay 53 side by side, it is apparent that, beyond the obvious difference of having an internally fused pin 86, the pins aren't laid out the same, i.e. 85 and 87 aren't in the same spots as they relate to base that the relay gets plugged into. Below is a picture of the two relays side by side, with the 53 being the smaller of the two:

So, question number 1:
If I use the 109 instead of the 53, the wires running into the existing relay base won't be correct, so I'm thinking I should probably just stick with the 53. In this case, I've now got an extra brown wire running out of pin 86. Should I just run this to ground on the body or bay somewhere or do I need to splice it into one of the other pin wires?
Question number 2:
Below is a side shot of the simplified relay/fuse bases with the associated wires protruding from beneath:

As you can hopefully see, there are 7 wires coming out of the GP relay base. My diagram only accounts for 4 of these (feed out to GP fuse, switched power to terminal 15, constant power to terminal 30, and wire to pin 42 on ECU).
My question is, what do I do with the other 3 wires? It's my understanding that they receive signals from various sensors to produce delays, light lamps on the dash, etc, but if I plan to just put a flip switch on the dash for glow plugs and use it for a few seconds at startup on cold days, can I disregard the other wires and just cap them off?
And stemming from that, question 3:
In order to put in a flip switch for the glow plugs, which wiring coming into the relay base should I tie that switch into? The switched ignition to track 15?

Question 4:
In an effort to ensure that I'm wiring things up correctly, it would be helpful to know which pins on the GP relay are which. Rather than seeing a 30, 85, 86, and 87 on the base of the relay, I've got a bunch of other numbers and letters as shown in the picture below:

Starting from the top left corner and going clockwise, I'm seeing 31, 30, ST, G1/2, DT, 86, and G3/4. Can anyone tell me which pins equate to 85 and 87?

Also, after poring through the Bentley and other wiring diagrams, I can see to identify what this bugger is:

It was part of the original harness and I've seen it present in the bay when I look at conversion photos, so I kept it in there, but honestly, I don't know what purpose its serving.
Question 5:
What is that piece of hardware with the covered clear cap and what do I need to do with the two large black wires coming out from it? Below is a picture of the wires that need landing:

Thank you in advance for any feedback! I'm learning a ton throughout this process and I feel like I'm getting into the home stretch! I've got the engine and trans mounted, all of the coolant and power steering hoses hooked up, power steering pump, fuel filter, and coolant bottle mounted, and now I'm down to the wiring.
Appreciate your time and assistance!
 

Alchemist

Veteran Member
Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
This is my take on what you have done so far.



Hello again!
It's been a while since I first asked some of these questions, and now I'm back into the wiring with more questions.
So, reading through this thread and with the advice I'd gotten from Alchemist, I put together a little diagram of what I "think" I need to wire the 3 key elements of this simplified setup (Relay 109, GP Relay, GP fuse) into the vanagon. See below:


Here are some sketches that may help you sort out the details.





Now, after trimming down my harness, below is what I'm looking at, similar to the images I saw earlier in the thread:

So, where I'm running into some questions is when I compare the diagram and what I think I'm supposed to wire vs. what used to be wired in the stock Jetta harness.
First off, the socket where I would have expected to have a 109 relay in the Jetta had a 53 relay, and coming out from the base are 4 wires, as opposed to 3. There was a relay 109 on the main fuse block in the Jetta, and if I pull that and compare it to the relay 53 side by side, it is apparent that, beyond the obvious difference of having an internally fused pin 86, the pins aren't laid out the same, i.e. 85 and 87 aren't in the same spots as they relate to base that the relay gets plugged into. Below is a picture of the two relays side by side, with the 53 being the smaller of the two:

Those relays are made this way so they only fit where they are needed for assembly line error proofing. Use the 53 wired as shown in the first diagram I posted.

So, question number 1:
If I use the 109 instead of the 53, the wires running into the existing relay base won't be correct, so I'm thinking I should probably just stick with the 53. In this case, I've now got an extra brown wire running out of pin 86. Should I just run this to ground on the body or bay somewhere or do I need to splice it into one of the other pin wires?

See the diagram posted above for the generic equivalent of a 109 relay. Pins 30 and 86 both connect to battery+, 87 supplies power to the ECU, IP, solenoids(N18, N75, N108) and sensors etc., Pin 85 connects to ECU Pin 42 so the ECU can control the relay.
Question number 2:
Below is a side shot of the simplified relay/fuse bases with the associated wires protruding from beneath:

As you can hopefully see, there are 7 wires coming out of the GP relay base. My diagram only accounts for 4 of these (feed out to GP fuse, switched power to terminal 15, constant power to terminal 30, and wire to pin 42 on ECU).
My question is, what do I do with the other 3 wires? It's my understanding that they receive signals from various sensors to produce delays, light lamps on the dash, etc, but if I plan to just put a flip switch on the dash for glow plugs and use it for a few seconds at startup on cold days, can I disregard the other wires and just cap them off?

Relay 180, which you have, is really an electronic control module. The ECU needs to communicate with it to turn glow plugs on and get feedback about the state of the plugs. You could use a simple relay under manual control, but the ECU will see this as a fault and will set a DTC resulting in a permanent MIL on. It is probably best and easiest to use it as intended following the diagram posted above. Note that the 50 amp fuse is in the supply line and not the output to the glow plugs
And stemming from that, question 3:
In order to put in a flip switch for the glow plugs, which wiring coming into the relay base should I tie that switch into? The switched ignition to track 15?
The 180 is not a simple relay, so there is no easy way to make it behave like one.
Question 4:
In an effort to ensure that I'm wiring things up correctly, it would be helpful to know which pins on the GP relay are which. Rather than seeing a 30, 85, 86, and 87 on the base of the relay, I've got a bunch of other numbers and letters as shown in the picture below:

Starting from the top left corner and going clockwise, I'm seeing 31, 30, ST, G1/2, DT, 86, and G3/4. Can anyone tell me which pins equate to 85 and 87?
31 is ground
30 is battery+ through a 50 amp fuse
ST is one of the lines used to communicate with the ECU
G1/2 supplies power to the glow plugs for cylinders 1 and 2
D1 is the other line used to communicate with the ECU
86 is Switched power from relay 109 pin 87
G3/4 supplies power to glow plugs for cylinders 3 and 4

There is nothing which equates to simple relay pins 85 and 87
Also, after poring through the Bentley and other wiring diagrams, I can see to identify what this bugger is:

It was part of the original harness and I've seen it present in the bay when I look at conversion photos, so I kept it in there, but honestly, I don't know what purpose its serving.

That is the coolant glow plug relay, which is used to help with warm up in very cold conditions. It is actually two relays in one case which gives some range of control over how much power is being used and how much heat is being produced. One of the relays supplies one glow plug, while the other supplies two plugs. You can then have one, two or three plugs working. The ECU monitors the relay coils, so if you don't connect it you will have a permanent DTC, but I am not sure if this will turn on the MIL or not.
Question 5:
What is that piece of hardware with the covered clear cap and what do I need to do with the two large black wires coming out from it? Below is a picture of the wires that need landing:


Those are the wires that connect to the coolant glow plugs. The larger one connects to the two outer plugs, while the smaller one connects to the center one. The plugs are located in the water outlet on the end of the cylinder head.
Thank you in advance for any feedback! I'm learning a ton throughout this process and I feel like I'm getting into the home stretch! I've got the engine and trans mounted, all of the coolant and power steering hoses hooked up, power steering pump, fuel filter, and coolant bottle mounted, and now I'm down to the wiring.
Appreciate your time and assistance!
 

Hoff6282

Member
Joined
Mar 22, 2012
Location
Michigan
TDI
2000 Golf TDI (sold), 2002 Jetta Wagon TDI (sold), 1987 Vanagon Weekender mid-swap to AHU TDI
As always, thank you for the incredibly thorough and insightful response, that is exactly the information I was looking for. Assuming I get this thing running in the next few weeks, I have a feeling that my first road trip should be to wherever Alchemist resides to buy some drinks!
 

Daragorn

Member
Joined
Nov 11, 2017
Location
Nordegg, AB
TDI
1983 Vanagon 1.9 TDI (AHU), 2000 Jetta TDI
Hey- this is a super helpful thread. I'm in the middle of swapping a dead AAZ engine for an AHU TDI in my 1983 Vanagon Westfalia. The new engine is in the van and now I'm sorting through the electrical.

Alchemist- you mention in one post that you have some sketches that may help sort our the details? I can't seem to find where these sketches are? I'm new to TDIclub so maybe I'm just missing something. Sounds like they'd be helpful if I can find them though.

Secondly- with the 109 relay...I picked up a standard relay and harness to replace the 109 relay but have my doubts about it. The 109 has an internal resistor but the relay I bought doesn't. I assume I want to find a relay that has an internal resistor?

As for the switched power to the ECU (pin 38), which wire from the Vanagon is best to use? Alchemist- you mention in an earlier post that switched ignition is typically a black wire on the Vanagon. Would this be the wire that goes to the coolant low level warning? Can I simply connect the ECU onto this wire or did you mean something else?

I probably know just enough to be dangerous so please let me know if it sounds like I'm going off track somewhere here.

Thanks!
 

Alchemist

Veteran Member
Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
Here is some info. Let me know if you need more help.

Hey- this is a super helpful thread. I'm in the middle of swapping a dead AAZ engine for an AHU TDI in my 1983 Vanagon Westfalia. The new engine is in the van and now I'm sorting through the electrical.

Alchemist- you mention in one post that you have some sketches that may help sort our the details? I can't seem to find where these sketches are? I'm new to TDIclub so maybe I'm just missing something. Sounds like they'd be helpful if I can find them though. OOPS! I think I did some clean up one day and they got lost. I will try to dig them up.

Found something.





Secondly- with the 109 relay...I picked up a standard relay and harness to replace the 109 relay but have my doubts about it. The 109 has an internal resistor but the relay I bought doesn't. I assume I want to find a relay that has an internal resistor? The resistor is there to suppress transient voltage generated by the relay coil on release. It is not absolutely necessary, but is good engineering practice to protect electronic devices. A diode across the coil with cathode to + supply will do the job too.

As for the switched power to the ECU (pin 38), which wire from the Vanagon is best to use? Alchemist- you mention in an earlier post that switched ignition is typically a black wire on the Vanagon. Would this be the wire that goes to the coolant low level warning? Can I simply connect the ECU onto this wire or did you mean something else? Sorry, I am not familiar with the details of the Vanagon, but any point that is live with the key the on or start will work. VW typically uses Black for this function.

I probably know just enough to be dangerous so please let me know if it sounds like I'm going off track somewhere here.

Thanks!
 
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Daragorn

Member
Joined
Nov 11, 2017
Location
Nordegg, AB
TDI
1983 Vanagon 1.9 TDI (AHU), 2000 Jetta TDI
Thanks Alchemist- that is helpful. I was able to find a 4 pin relay with a built in resistor so I'll just use that for this project.

A few other questions:

For the power supply relay- I'm planning on adding a fuse because I don't think it will have any protection the way it is being set up. If necessary, what size fuse would you recommend and where is the best place to put it?

Earlier in this thread you were discussing the brake light switch...just want to make sure I understand- since I'm not using cruise, should I simply ground wires from pin 44 and 20? What about pin 17 (clutch pedal switch)- should this be grounded too?

I'm sure I'll have more questions as I go- thanks for the help.
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
I would hook up the brake input, a simple SPDT circuit. I tried to find the reference I used but could not. Basically it said that a brake input is used by the computer to reduce slowdown shudder when you are braking from higher RPM’s. It doesn’t seem to be a big deal to those who don’t hook it up, but if you are the OCD type (like I can be) with that sort of thing, it’s easy circuit to wire in.

EDIT: clutch circuit too for the same reason, tells the computer you just removed the load from the engine
 
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