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!