'02 Glow plug harness replacement (56k warning!)

[tdi_allan]

Well, the CEL finally drove me over the edge. I've had the new gp harness for a while, but cringed at the thought of crimping wires on my 2 year old car. Besides, why was the wiring so long on the new harness? Bentley was suspiciously quiet on the subject. Follow along as I chart new territory (for me, anyway... ) I even have a few pictures to go along with the story!


It always pays to start with the right tools. 10 mm, 13mm sockets, screwdriver, shop towels, a bottle of water and the new harness.


Here is the part number in case you need it.


After removing the engine cover, battery and airbox, this is what you see. That black plastic thingamajig comes off fairly easily after you pull up some of the hood trim at the top.


Jackpot! The white arrow points to the double-secret gp harness connection. I was quite surprised to find the gp harness wrapped with a bunch of other wiring! At this point, I was beginning to see why dealers charged a bunch of green to replace this.


So, I carefully unwrapped the cloth electrical tape from the wiring that the gp harness was wrapped in. Yes, this took a while. No, I did not cut any important wires.




These are pics of the separated gp harness from the rest of the wiring it was trapped with. Note the TT shifter I installed while waiting for Dad to return with something suitable to re-wrap the wires in.


As long as all of this was apart, it was Cage Mod time! One of these days I'll get the rest of the car's connectors (this one and MAF so far.)


This is what I used to re-wrap the wiring. Not nearly as sticky as the cloth junk. I wrapped the gp harness separately, to make future replacement that much easier.

For everything else, installation is the reverse of removal.

Hope this helps someone out there, its a lot of work but worth it to do the job right. Those of you with pre-02 cars can crimp and be satisfied because there is no harness connector on those applications.

[TDICa]

You know this was covered under dealer warranty. Yes they do a sloppy cut and crimp job, but I was too lazy to do it myself. Good write-up - I probably redo mine when I have some free time on my hands.

[Wingnut]

Great job. I will post a link to this writeup in my "Glow plug how to" thread for those who plan to do it too.

[tdi_allan]

Thanks Wingnut, I had no idea my post would be worthy of inclusion in "Glow Plug 101" Now that I know where everything is and have the gp harness separated, it is likely I will never have to do the job again.

[cage]

I wondered. When I did mine I asked and people said that you had to cut it. That the harness is a generic one used for all kinds of VW diesels. Oh well, next time I'll do it right.

[AlanTDI]

Nice job tdi_allan.

On my 99 Golf TDI, my local mechanic did the harness replacement.
Maybe if my 02 harness acts up, I can do it
Alan

[dzlchef]

Thanks for the write-up. I am planning on doing this soon for the same reoccuring problem on my 2002 and was dreading undoing all the wire wrap and then I had an idea. Why not just cut out the old harness and connector and just wrap the new wiring harness along the same path of wires. There is no need to unwrap everything if you're not going to use the wires anyway, right? Who cares if there are some loose unused wires wrapped in the bunch with the others. I think that I just saved myself a lot of extra time.

[mycruiseagent]

... Why not just cut out the old harness and connector and just wrap the new wiring harness along the same path of wires ...

What dzlchef said. The value here is the location of the mystery connector - that said ... great find and write-up!

MCA

[tdi_allan]

What dzlchef said. The value here is the location of the mystery connector - that said ... great find and write-up!

MCA

Excellent point. Where were you guys in September? Oh well, it was fun unwrapping and rewrapping the wiring harness...

[Nutsnbolts]

As a footnote, I think it might behoove those of us who have the pre-'02 models to get that connector and install it in the secret location should we ever have to change the harness. As stated before, it make the change that much easier, and you will thank yourself if you ever have to do it again. Fortunately, I haven't been down this road yet (looking for something wood to knock on), but thanks for an excellent and informative post!

-Rich

[MOGolf]

As a footnote, I think it might behoove those of us who have the pre-'02 models to get that connector and install it in the secret location should we ever have to change the harness. -Rich

the 'secret connector' had been previously posted, and is the same location for pre-02 models. The pre-02 models have just 2 heavy gauge wires at the connector. These go all the way to the gp harness. Each wire then feeds 2 gps inside the harness pre-02.

[Nutsnbolts]

Thanks!!!

[CGR]

Can someone give me the part number for the four wire harness. I can't make it out off of the picture. I have tried two dealers and the both say that the harness for my 02 is the 2 wire kind. The one dealer insists I am wrong and that I have bad info on my 02. The other dealers mechanics agree with me and that dealer has a 4 wire harness in stock for an 03 with a part number of 038 971 782 C

The parts guy and myself are thinking the harness they have for the 03 will work. Has anyone else run into this problem?

[weedeater]

IIRC, the change over to the 4-wire occurred in the middle of the 02 model year.

[kirmet]

I have my 02 tdi tore apart today to check the GP's and harness and would like to know a couple things.

Whats a TT shifter?

What is and why is it called "double-secret gp harness connection."?

Last but not least what is the cage Mod?