A3 / B4 glow plug relay and fuse location

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
none, 2014 Chevy Volt, 1988 Bolens DGT1700H
So where is that selonoid valve located at? What is the item number do you know?
THe solenoid for the fresh air / recirculate change is on the left inner fender / mud guard of the B4 Passat. I don't know where it might be on the Cordoba. Locate the fresh air intake at the base of the windscreen under the hood / bonnet. Look for a small (4 or 5 mm?) air hose that goes to that area. Follow that hose to its other end.
 

mike000

Well-known member
Joined
Jun 11, 2012
Location
Hartford, CT
TDI
1Z TDI swapped '90 Jetta
Where exactly does the heavy gauge positive feed for this GP fuse come from? Where in the CE2 fuse box? TDI swapped mk2 and I totally just realized there was a heavy gauge red wire coming out of this fuse holder and I never hooked it up. This would explain my nightmare cold starts. I believe it's like a 4 or 6 gauge wire with a yellow(?) connector?!
 

Mcgink

Veteran Member
Joined
Oct 15, 2004
Location
South of Boston MA
TDI
I-Red,"The Passat formerly known as Harlequin" 97 B4, a non VW GTDI too
Anyone know the P/N for the jumper relay used with the FA wiring?
It's in this thread somewhere, but it's an obsolete part. You can make one or repair the one you have.
It's fixed, I took the part from relay position #12 from my B4 sedan and compared it to the 103 relay which was in my B4V.
This is what they look like opened up:

I'm thinking that at some point that the PO had a cold start issue and a Tech replaced the wrong part. The part on the right is callled a "Bridge" and the part # is: 3A0 941 817. FYI the part is obsolete according to the local VW dealer's parts dept.
Without the info/pics in the begining of this thread, I would no doubt be still scratching my head trying to diagnose the root cause of my cold start issue.
Thank you
 
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Stoneage

Veteran Member
Joined
Oct 12, 2013
Location
Portland, Oregon
TDI
1.9 Mk3 Jetta TDI
The question of which fuse or relay is the one for the glow plugs won't go away. Perhaps this one thread will eliminate the 40 or 50 each year that ask the same question over and over.
The fuse for the four cylinder glow plugs is located inside the cabin above the fuse and relay mounting block. Please see the images below for the locations on the B4 Passat (near the top of the inside firewall), and on the A3 Jetta (at the top of the fuse and relay block).

1996 B4
On the North American market 1996 Passat the glow plug relay is the one in position #12 of the fuse and relay block just above the driver's feet. The relay is identified by a "103" printed on its top. Note: The Bentley manual electrical schematic has a typo which indicates this glow plug relay is marked with "104". The image below shows a typical 1996 B4 relay layout. The glow plug fuse location is similar to that shown in the 1997 B4 image to follow.
This wiring harness requires the BK or GQ ECU.



1997 B4
On the North American market 1997 Passat the glow plug relay is moved to a remote location above the main fuse and relay block. There were several other wiring changes made at this transition. The glow plugs relays are not interchangeable between the early and the late wiring harness changes. The glow plug relay is now marked "180". A 'jumper relay' is installed in position #12 to allow electrical power to feed to the remote 180 glow plug relay location. The other relays in the relay and fuse block are positioned similar to those shown in the previous 1996 image. The image below shows the mounting location of the "180" glow plug relay in the 1997 and also the glow plug fuse location in both the 1996 and 1997 B4. Thanks to TonyJetta for the edit of PaulB's picture showing the 1997 relay and fuse location.
This wiring harness requires the FA ECU.







Important Note: The wiring harness change in the B4 TDI took place part way through the 1997 model year. According to the Bentley manual the change over took place at the end of October 1996 for the last of the early, BK/GQ/103 wiring harness, with a November 1996 start for the later, FA/180 wiring harness. Very early 1997 models, those built in June through October of 1996, might therefore have a harness similar to the 1996 models and would require the "103" relay.
The glow plug relays are not interchangeable between harnesses. The relays and/or the wiring harnesses can be damaged, and wiring harness fire inside the cabin is a real possibility, due to the dead shorts created by improper glow plug relay use.





1998 A3
The North American market 1998 A3 has the "180" glow plug relay attached above the main relay block. The glow plug fuse is mounted just above the glow plug relay, not separately on the inner firewall as on the B4. Also note in the image below that there is nothing in the lower right relay socket (location #12). This is a difference from the 97 B4 TDI which needs a jumper to feed power to the glow relay 180.
Note: The installation of a #12 jumper relay from a 1997 B4, or the installation of a "103" or "180" glow plug relay in this vacant position with the 1998 A3 wiring harness can also cause damage to electrical components and possibly fire from dead shorts.


Note: The Bentley wiring schematics show a change in the wiring of the glow plug relay during the A3 TDI production years. I have no further knowledge of the differences than what is described below in post #7.
Thank you
 

Stoneage

Veteran Member
Joined
Oct 12, 2013
Location
Portland, Oregon
TDI
1.9 Mk3 Jetta TDI
98~99 A3
In the 98 A3 the socket #12 is empty. The glow plug fuse is before the glow plug relay. The fuse is always hot. Again there is no easily accessed test point for either.
Note that the Bentley A3 service manual's electric schematic, sheet 97-415, indicates the glow plug wires from the glow relay are 0.5 mm in cross section. The correct size is 5.0 mm cross section.

So I check the fuse above the relay and it was burnt out. Where can I find a replacement fuse? its a 32 volt 50 amp fuse. The relay is marked with 53 not 180. Is this an issue?

I pulled the blown fuse from the spot right above the relay marked 53.


EDIT* This is the layout of my relays under the dash
 
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Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
none, 2014 Chevy Volt, 1988 Bolens DGT1700H
The relay marked with the production code 53 is an ordinary, run-of-the-mill relay such as would be used for the horn or fog lamps or any of a number of functions, but not for the glow plugs.
All those fuse and relay modules above the main array can be moved around, taking their wires with them so the arrangement map varies whether it was Johann or Juan building that car.
I don't have a Bosch cross reference but the fat red wire going away is another clue that the 53 relay isn't involved with that fuse holder.
Most auto part stores will have the high current blade fuses. I know the AutoZone near my house does.
 

Stoneage

Veteran Member
Joined
Oct 12, 2013
Location
Portland, Oregon
TDI
1.9 Mk3 Jetta TDI
The relay marked with the production code 53 is an ordinary, run-of-the-mill relay such as would be used for the horn or fog lamps or any of a number of functions, but not for the glow plugs.
All those fuse and relay modules above the main array can be moved around, taking their wires with them so the arrangement map varies whether it was Johann or Juan building that car.
I don't have a Bosch cross reference but the fat red wire going away is another clue that the 53 relay isn't involved with that fuse holder.
Most auto part stores will have the high current blade fuses. I know the AutoZone near my house does.
Ok thanks I'll go check them out. Do you know which one would be my glow plug relay?
 

Stoneage

Veteran Member
Joined
Oct 12, 2013
Location
Portland, Oregon
TDI
1.9 Mk3 Jetta TDI
I ended up figuring it out the one to the left of the 53 relay after some googling came up with this one being the glow plug relay. If anyone runs into this in the future not being marked 180. This one is your glow plug relay.



The one with the arrow pointing at it.
 

SpencerI

Active member
Joined
Nov 22, 2013
Location
Mountlake Terrace Washington
TDI
98 Jetta TDI 1.9L
I know i'm jumping in, but quick question. Is there a fuse for the main glow plugs on a 98 Jetta? If so is it behind the fuse box or located somewhere else on the car. I know there is a strip fuse in the engine bay under the rain drip tray. What does this fuse go to?
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
none, 2014 Chevy Volt, 1988 Bolens DGT1700H
Fat red wire screwed to a socket headed cap screw at one end of the strip fuse? Black wires from underneath and a plug conncetion underneath as well?
That's the fuse for three coolant heaters to help warm up the car a bit quicker.
 

Vwscream

Veteran Member
Joined
Jan 19, 2014
Location
Chicago
TDI
90 Corrado 1Z, 97 1Z Passat, 85 Golf NA
Has anyone run into GP issues when using Jetta ECU JB part number? I have not noticed anyone mention the later ECU used in 96 Passat. Will there be GP operation problems do to the feedback circuit?
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Nobleboro, Maine
TDI
See signature for TDI's
I have a JB I use in my '97 and '96 Passat's all the time and have never had an issue so long as the year specific chips are installed. The wiring is different between the models which is why the chips are year specific.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
none, 2014 Chevy Volt, 1988 Bolens DGT1700H
The ECU designation depends solely on the chips installed.
Your computer might say "Windows" on the outside but load Linux and it's not a windows machine anymore, is it?

Take an ECU with a "JB" sticker on the outside of it, remove the JB program chips, install the FA chips and it's an FA ECU no matter what the sticker reads.

The odd one is the "BK" ECU as the circuit boards have completely different configuration and the other A3/B4 ECU chips won't even plug in.

The North American market harness / case / chip compatibility is shown below

wiring harness----------------ECU case ID-----------chip ID
1996 B4---------------------BK (black plastic)--------BK
1996 B4---------------------ED, FA, GQ, JB----------GQ
1997 B4---------------------ED, FA, GQ, JB----------FA
1997~1999 A3---------------ED, FA, GQ, JB----------ED, JB
 
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Vwscream

Veteran Member
Joined
Jan 19, 2014
Location
Chicago
TDI
90 Corrado 1Z, 97 1Z Passat, 85 Golf NA
Thank you.

This is what I needed to know. I'm going with using JB ECU in chassis that had the BK ECU hard plastic case. I was planning on getting a chip after all the quarks are figured out. Wanted to make sure the ECU won't case any issues with different wiring.

Thanks again.

The ECU designation depends solely on the chips installed.
Your computer might say "Windows" on the outside but load Linux and it's not a windows machine anymore, is it?

Take an ECU with a "JB" sticker on the outside of it, remove the JB program chips, install the FA chips and it's an FA ECU no matter what the sticker reads.

The odd one is the "BK" ECU as the circuit boards have completely different configuration and the other A3/B4 ECU chips won't even plug in.

The North American market harness / case / chip compatibility is shown below

wiring harness----------------ECU case ID-----------chip ID
1996 B4---------------------BK (black plastic)--------BK
1996 B4---------------------ED, FA, GQ, JB----------GQ
1997 B4---------------------ED, FA, GQ, JB----------FA
1997~1999 A3---------------ED, FA, GQ, JB----------ED, JB
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Ok, so I'm sorting through my 98 AHU wiring harness in anticipation of stripping out all the excess stuff and getting it bundled up for install in my 90 B3V and I notice a very large red wire going to an external relay mounting block that I think is the glow relay (180) block.

My A3 Bentley doesn't have the correct wiring diagram for the later Mk3 TDI glow circuit, it only has wiring diagram for the #12 mounted glow relay which I think is probably just applicable to the AAZ TD engine models.

At any rate the cut big red wire goes to the glow relay block but because I don't have the correct wiring diagram I don't know where that wire originates. Does it originate at one of the #30 circuit spade terminals on the fuse / relay panel or does it come from somewhere else?

Someone attacked this car before I got to it, all the relays were gone and some of the wiring to the interior harness was cut.

Fortunately all of the wiring for the Ecu appears undamaged.

If someone has the real wiring schematic for the 98 up AHU Mk3 could I get a copy of those pages?

Thanks Steve
 
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jerryfreak

Veteran Member
Joined
Feb 16, 2004
Location
Nor Cal
TDI
02 Jetta GLS sedan @250K, 150K on B99, 99 Jetta sedan 250k, 20k on B99. 2015 tdi sedan, 35k
my 98 jetta does not look like the '1998 A3' pic on the first page. the relay is in the same position as the '180' pictured, and has the 50A fuse at the top, but is missing the '180' markings (perhaps it was replaced). i also have a '175' marked relay inthe lower right cornar (for something else? ive seen some pics with the glow plug relay in the lower right corner there

thanks
 

TDIL3dad

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Joined
Jan 21, 2012
Location
N. VA
TDI
96 B4, 96 B4V project
Lug Nut -
I am interested in upgrading my B4 turn signal clicker sound to the much louder B5 sound.

In researching the B5 relay for turn signal (loud clicker sound), so far I'm finding that it is built into the B5 flasher switch (?), and does not appear to be interchangeable with the B4.

Am I looking at right B5 part?
Is there an interchangeable relay from the B5 or other VW that I can install in my B4 to give me the loud clicker sound with the turn signal?

https://www.youtube.com/watch?v=-SomJgcIm9I
 
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Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
none, 2014 Chevy Volt, 1988 Bolens DGT1700H
PM sent.

and, No, I wasn't waiting here for an inquiry. It was by sheer happenstance that I logged on just a few moments after your request.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
my 98 jetta does not look like the '1998 A3' pic on the first page. the relay is in the same position as the '180' pictured, and has the 50A fuse at the top, but is missing the '180' markings (perhaps it was replaced). i also have a '175' marked relay inthe lower right cornar (for something else? ive seen some pics with the glow plug relay in the lower right corner there

thanks
You should have no relay in position 12, that needs to come out of there. By mid-late 1997 production position 12 had been abandoned for GP relays, the large 180 relay above the fuse box and the maxi fuse replaced this whole setup.

My 1997 has the 180 relay above and nothing in position 12, you should have the same.

As for your 180 relay being unmarked you need to find a part number on that relay and verify that it's the correct relay, it should be a 7 pin relay. If there's any doubt you should replace it with a known good correct relay.

BTW, position 12 has always only been for Fuel pump (FI gas cars) or GP's (diesel cars).

It wouldn't be a bad idea to take a look and make sure someone hasn't been messing with the wiring too.

Steve
 

algirdas

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Joined
Jan 23, 2009
Location
Cincinnati,OH (Dubwerx)
TDI
98 jetta AHU
Have a '98 Jetta AHU with a glow plug monitoring code that wouldn't clear using VCDS.
Harness is fine. Checked all the glow plugs-OK, then the '180' relay-OK.
Turned out to be the 50A maxi fuse was blown. Replaced it, cleared code, fixed.
 

hummelmike

Well-known member
Joined
Dec 30, 2015
Location
Hillsboro Mo
TDI
1997 jetta tdi, 2000 Golf tdi
Has anyone ran a main line from fuse area on glow plug to glow plugs on 1997 tdi seem to be having issues with glow plugs and tested all of them and seem good. Is there anyway they could test good and still be bad?
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Has anyone ran a main line from fuse area on glow plug to glow plugs on 1997 tdi seem to be having issues with glow plugs and tested all of them and seem good. Is there anyway they could test good and still be bad?
Unlikely that they would test good but be bad. Did you read the post before yours where he talks about the maxi-fuse being burned out? I would check that.

Steve
 
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