What are these relays on the firewall for?

[92EcoDiesel Jetta]

Damm, it's always something!  I found my battery dead today..I started tracing which of the 5 red wires on the + battery terminal the current draw was from and found it was one that goes into the harness into the cabin (presumably going to the fuse relay panel). I can hear a couple of things clicking as I connect/disconnect that wire. Turns out the relay marked 111 in the pic was clicking and also the air cond compressor clutch was also clicking. I assume that relay feeds the clutch? This is with the key off. Why is there power to the compressor clutch with key off?

[92EcoDiesel Jetta]

[92EcoDiesel Jetta]

What are the big lettering on all the relays? Such as 111. Do they correspond to anything in the Bently wiring diagrams?

[Jay]

The numbers indicate what the relay is used for.

There is a comprehensive relay guide on another forum (mainly for GTI's though).

A quick google finds this:
http://forums.vwvortex.com/zerothread?id=4257880

hth

[92EcoDiesel Jetta]

I Googled the p/n 357 906 381 B on the relay and it's a aux fan relay. Come to think of it, I recently noticed the radiatot fan staying on for a minute or  two after turning the key off. My guess is this relay has something to do with the aftercool and not releasing. Back to more troubleshooting. It's always something with these old cars huh?

Still would like to know what the big number 111 on the relay signifies. Anyone?

[kane66]

On hot days my radiator fan always stays on for a few minutes after I turn off the car.

[Rabbit on Roids]

lol @ fans. the fan in my jetta never has worked, and the fan in my rabbit, isnt in my rabbit, its in the shop.

[Powered by Spearco]

The number on the relay is called the controll number, and is the same number of relay as an '96-'99 gas, 2.0L and VR6 secoundary air pump relay's. But I'm willing to bet its for your glow plugs and the other is for the fan. Unless the fan relay is mounted to the fan shroud like all other MK2's with AC. Look at the wiring going to the 111 relay, are the colors of the wires the same as the wiring diagram? I think there will be 7 wires used for the glow plug relay. Pwr in, pwr out, key on, cranking position, glow light, temp. sensor and ground.

[Quantum TD]

Both relays run the 3-speed fan. The ECOdiesel is the only MK2 model that I know of that has a 3-speed fan, although the Corrado VR6 uses the exact same fan shroud and motor setup, but with a different control system. The Corrado uses an integrated relay box that's like the MK3 and MK4 boxes that mount to the driver's fender.

The larger of the 2 relays is for the highest speed, the smaller for the mid, and I think the low speed runs straight thru the fan switch itself (low amps?)

If your fan runs for a few minutes after park, that's normal. More than about 3 minutes, it's time for a new fan switch.

You can test the different speeds by pulling the plug off the fan switch.

1) Turn on the defrost (or AC if equipped) and the interior fan. That's one speed (high)
2) Determine which of the 3 wires to the fan switch plug is constant power (should be plain red). Then jumper it to the adjacent wire terminal(usually red and white) on the plug. That's the second speed (low)
3) Jumper the red terminal of the plug to the far terminal (usually red and black). That's your 3rd speed (mid: controlled by relay #98 on the firewall relay box).

The #111 relay appears to be connected to your AC system (looking at a spare harness on my floor here). The RED wire with a YELLOW stripe activates the #111 relay. The power comes from the thick red wire to the relay box (constant power). It comes from the fuse mounted to the relay box, which in turn is directly connected to the battery. When the RED/YELLOW wire receives power, it triggers the relay, and bridges the power to run the high-speed fan thru the BLACK/YELLOW wire.

The RED/YELLOW wire gets its signal from the AC switch in the coolant jacket (BROWN PLUG with 4 wires leading to it). Several criteria must be met for that RED/YELLOW wire to get power.
1) There must be charge in the AC system. The power runs through the High-Pressure switch on the AC lines (2 green wires)
2) The AC clutch must receive power from the interior of the car, thru the high-pressure switch.
3) The AC cutout/run switch on your heater control is engaged. It will only do this with POWER ON in the car, and the paddles set to AC, Max AC, AC bilevel, or Defrost.

If the BROWN coolant switch is BAD, then the RED/YELLOW wire could get power by bridging to the RED wire at the plug. I would imagine that the BROWN plug acts like a temp-relay. It's allows a relay-like connection between the RED and the RED/YELLOW wire on the plug, when the GREEN and GREEN/YELLOW wires bridge the contact. It will disconnect the contact if the engine temp gets too high (over 220C I think).


That's the logical place to start. One way to do so is to replace the switch (should be like $10-30). Another is to look for power at the GREEN wires in the engine bay when the key is off. There should be no power to the green wires when the key is off.

If there's power, then it's time to work back into the cab.

I had to trouble shoot the whole system on a 1991 ECODiesel. Someone crossed the terminals at the relays (they actually unplugged the terminals and swapped them around). The result was a burned out ground wire leading into the cab of the car. After fixing the relay terminals and putting in a beefy ground wire, everything worked great. Not much fun though...

[Quantum TD]

P.S. Don't bother looking in the Bentley. I'm 99% certain that it does not cover this wiring setup. I searched and searched. Nothing. You'll just have to take advice, and/or figure it out for yourself.

[92EcoDiesel Jetta]

Quantum TD, thanks so much for the detailed info! Bummer the Bently is so lacking for the Ecodiesels. Still can't believe it's the official VW manual for these cars. I wonder if the dealer has a better wiring diagram for it. I will call them monday to find out. In the meantime I will take all the advice you are willing to give. 

[Vincent Waldon]

Pretty sure the current flow diagram on page 258 (1990-1992 Canadian TD) is the correct one... it shows a separate fan relay in the engine compartment and is the correct years for the Eco version.

[Baron VonZeppelin]

Sounds like you need a new 111. I coulda told you that !

No but seriously, you're lucky to have good enough hearing to hear those things click. I can't hear any of the clicks on anything on my cars.

I was told those big numbers printed on the relays were for assembly workers in production. But that person was not a former assembly line worker.
Most all diesels have 60 on the Gplug relay and that number can't seem to be corelated to anything/any parameter number published either on mk2.
If not mistaken.

Now everybody's gonna be wanting a fancy 3 spd fan like you have.
How many wires come from the main plug-in that plugs into fan ?

[Baron VonZeppelin]

I had to trouble shoot the whole system on a 1991 ECODiesel.... Not much fun though...

That musta been a ReallY nice car to go through all that hassle. ouch
Blessings to you brother

[92EcoDiesel Jetta]

Pretty sure the current flow diagram on page 258 (1990-1992 Canadian TD) is the correct one... it shows a separate fan relay in the engine compartment and is the correct years for the Eco version.

Don't have my Bently handy but I found this at the Bently site under updates and corrections. This one is for air cond.

http://www.bentleypublishers.com/isbn/9780837603421/9780837603421/gallery-2980-8.html