Mk3 Golf TD glow plug light problem

[steevz]

Hey guys,

Love the forum, glad I could finally join.

So my problem is hopefully a simple fix. When I turn my key, my glow plug light doesn't come on. I removed the cluster and replaced the lamp, same issue, I also swapped the new lamp for the e-brake lamp and the lamp still doesn't work (Just to rule out a faulty new lamp.)

I know the glow plugs are working great because in -10*C if I leave the key turned for 8 seconds it fires up in a 1/4 turn. Starts excellent, runs excellent only issue is the glow plug light not coming on.

Thanks,
steevz

[the caveman]

I wouldn't be suprised if it's not a cold solder in the cluster, but i'd check for a signal out of the relay also. that being said ,if you can get your hands on a good relay to try first

[Vincent Waldon]

MK3s have an engine control module that runs the glow plugs, glow plug light, and drives the actual glow plug relay:



If you can find someone with a Bentley service manual you might be able to figure out which pin of the ECM leads to the glow plug light and run a few tests / hot wire it temporarily to see of the light comes on.

Unfortunately MK3 clusters are notoriously unreliable..so as Caveman points out the problem could just as easily be the cluster.   The glow plug fuse and actual relay aren't related to the cluster light.

[steevz]

I was thinking that it might be a bad solder joint as well. Everything is working but the light, so I'll check that first. Cluster is easy to pop in a few minutes.

Also, another cluster issue.. when it's cold my speedometer doesn't work properly. Moved slowly and is inaccurate and will stick, once warm it works fine. When I pulled the cluster I noticed there isn't a speedometer cable like my mk2 had, so I'm guessing it's all electric? Anything I can do to test this?

[steevz]

Solution to speedometer issue anyone?

[vanagonturbo]

Do you have VAG-COM or similar diagnostic tool?

[steevz]

Oh yeah, I do have a vag com with obdii from a 98 passat I had. But my golf is a 94, thought they didn't release obdii until 96? It looks like an obdii plug.. may as well try and plug it in.

[Vincent Waldon]

There's no computer, so nothing to talk to Vag-com.   

The Bentley service manual has the full troubleshooting process... basically yon need to confirm the Vss sensor on the transmission is working (using a multimeter) and then work your way back if need be. 

[vanagonturbo]

You crazy Canucks get the cool cars.. I must admit, anything that I have worked on with an AAZ was never a MKIII

VSS input is related?

[Big Daddy Roth]

two issues withe the cluster tells me you have solder issues. Check the cluster PCB for solder breaks around the input plug.

[vanagonturbo]

Perhaps before soldering the pcb, check the input from the GPR and see if it is sending a signal to the cluster to turn the light on? Not sure what pin because I am not near my Bentley manual at this time..

[Big Daddy Roth]

From A2 resource: (look under electrical, CE2)

U1/08    Gauge Cluster Glow Plug Light (diesel only), MIL Light (Passat VR6)             Glow Plug Relay Pin 9      Green/White (diesel), Yellow/White

G2/05    MIL Light from Motronic ECU (Passat VR6)                                              Glow Plug Relay Pin 9      Yellow/White

So the signal goes from the 136 controler, into the fuse panel at G2/05, internaly conected to pin 9 at the relay (trigger), then out to the instrument cluster at U1/08. Your wire colors may be different, but the pin outs are the same.

VSS:

U1/11    Gauge Cluster Speedometer Vehicle Speed Sensor                                                                      White

G1/11    Vehicle Speed Sensor Gauge Cluster       (signal from sensor into fuse box)                                     White/Blue

G1/06    Motronic ECU Pin 34, Vehicle Speed Sensor                          Main Fusebox Ground                         Brown/Red

I forget if the VSS has two or three wires. If it has a third, it should be 12V supply.

You follow me so far?

[steevz]

Thanks you guys are awesome. Just need a couple acronyms cleared up.. pcb? vss?