Hello,
I am new here, registered in March... From that time I was waiting if my mechanic will fix my C5. Well, last week I took a car from him and now my brother (car electrician) will try to put in one piece. I will put some pics here and ask you some question.

I bought engine harness from 99 C5, because is better (and 97 harness was hard to find) I paid $150:









We checked all wires one by one and it is 99' bot probably for manual gearbox.
As you can see here:

upper three connectors are from my car, 97' C5, connectors bellow are from "new" 99' harness. I have to change round one 99' to fit black square one 97' Do you have any wiring diagram how 97 and 99 is done, please?

Another problem, on passenger side some wires goes from underdash to engine and after crash there is something missing, any idea which connector or what it should be there and again, wire colors and where to connect?


And here is PCM, I bought it like 99' but in catalog is shown like 01-02, will it fit OK?


and mine:


If you read until now, thanks for patience and any suggestion is welcome.

Thank you
Roman

 

The 97 is a unique car being the first of the C5's built and there were several changes between 97 and 99. If your trying to rebuild a wrecked 97 I would strongly recommend only using 97-98 parts and getting a set of service manuals.

Go to www.gmpartshouse.com, the manuals can be purchsed for right around $100 and while your there check on his prices, he can get you brand new parts that will be correct for your car.

Do you really want to spend a lot of time rebuilding this car only to be plagued by wiring problems?

 

97' engine harness is hard to find and bloody expensive (if you will find it). But as we checked, it is the same just needs to re-pined in ECM side. I also checked 99-00 harness and it is the same with 01-03 harness, so I think if we will be able to swap this harness, there should be no problem later.
Have to speak with friend of mine, he has a 3 big service manuals. Or is it possible to find this manuals on CD or DVD? Any idea?

And question about ECM, I saw on ebay that is possible "custom" tuning that they will put VIN inside and they are able to disable VATS. So then is immo out of function?

I don't have such strong market potentials here in Czech republic to buy whatever I need, so have to try this way. So I am going to obtain service manual, as I can see without it is "mission impossible"

 

See if you can get a DVD manual from somebody on the forum. If you go with paper manuals you may need two sets. One for the 97 and the other for the 99. That is the only way you will be able to compare the connectors and which pins are used. The biggest problem you will have with the manuals is the lack of an overall schematic showing all pin outs. Even in the paper versions of the manuals the schematics are broken down into smaller elements that are fine for showing on a computer screen but you have to combine many pages from many sections of the manual to get a complete picture of the harness.

Bill

 

I'd suggest getting the manuals for your year, 97. There are differences in the wiring between years. Then ask for people to send you digital copies of the wiring diagrams from a 99. The CD manuals are kind of a PIA to use, and may not even work for you. So, I would suggest that you get the real manuals.

You have a A4 transmission right? If so, the manual wiring harness is going to be very hard to use. The engine wiring harness connects the transmission wiring harness to the PCM, and to the under hood fuse block. The A4 has a lot more wires going to the PCM than the manual gear box, so to make it work you would have to buy new connectors and add several wires. The reason you would have to buy new connectors is that some of them you will not be able to remove from them or even add wires to them.

It would be easier if you could seperate the needed connectors and wires form the old harness, and just throw out the ones on the new harness. Not sure if you can do that. It would be a big mess, but one that is manageable.

There are several places that can do whats called mail order tune, and some will send you a PCM (no need to send them one). You just tell them what you need, and then it should just plug in.

Could not tell you right off what those loose wires are to, I suspect you would have to spend a lot of tiem with the wiring diagrams to figgure it out

 

I have both paper and DVD manuals and never use the paper ones anymore. There isn't a good table of contents or index in the manuals and the DVD manual allows searching and hyperlinking. The GM tech writers designed the manual for use on a computer and all the paper manuals are is a print out of the computer version which leaves a lot to be desired. You can see the hyperlink locations highlighted in the paper manual but of course they don't tell you where to go to find the information and the index doesn't either. It is really fun to search through 1400 pages looking for the information you need. With the DVD manual you just click on the hyperlink and you go to the section you need to go to.

Bill