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GT top swap wiring question...

boosted98

boosted98

New member
So, I bought a 99 grand prix GT that has been top swapped with the GTP top end...the PCM is a 2001 GTP PCM...the GT harness is in the car, with the BBV and MAP spliced in....I really would like to not have a cut harness in the car, so I would like to just swap in a new harness...what year of GTP harness would I need? Or would you recommend just going with another 99 GT harness and using ZZPs swap wiring? At least ZZPs will plug in, so I will have all connectors and not splices wires....I know its a minor thing, but im very particular....main thing holding me back is knowing which harness to run...I know 98 doesnt have VATS, but im not sure if that will make a difference, or going outside of the 99 year to 00+ years will make a difference or what. Any help is appreciated. Thanks guys!
 


Can you get a picture of the problem area please. I extend, modify etc harnesses all the time and no one would ever know that I've been there except for some clean black tape on the loom. If things are running properly, why change the whole harness unless something is seriously wrong, you can make it look factory clean for a lot less effort.

I'd go with a 99 harness if that's what you car is... then have your pcm programmed to the right stuff as a 99 instead of a 2001 and put the right vin on it.
 
I can get a few pics in the morning when im with the car...its just the 3 MAP sensor wires, ground for the ICM, and the 2 BBV wires...but, I really REALLY like to keep all the connectors there and have an uncut factory harness...I know I could get it to look factory...but it just bugs me for some reason....im real weird about those kinds of things....and yea, the PCM is a 01 GTP PCM, I still have yet to tune the car, so hopefully that PCM will work with this harness...
 
98-01 should be the same for the harnesses.. Might be minor changes.

You do realize your factory harness has cuts in it? They are called splices. Simply a bunch of grounds etc or power wires all exposed and then with a metal crimp over it. If you pulled back the tape and added solder to it, it wouldn't corrode and would be a better connection.

All I'm trying to convey here is you can do a better job than the factory or the guy that obviously left yours looking poorly.
 
Ok, cool.

And you do make a good point, I forgot about that....it would still bug me...but not as much I guess....and better than $250ish for a harness, or cheaper at junkyards, but, finding one in tact will be the kicker there I guess lol...I have done quite a bit of soldering...but mainly use the 3M crimp connects for this kind of stuff...what would you suggest to get them to where ill pretty much never have to mess with them again?
 
I solder and use heat shrink tubing. I'm actually going to be doing one in the next couple days for a NA to SC swap I'm working on. Also just swapped my car from SC to NA and redid the map.

I take about 1/2" of coating off the ends of the wires, twist them together so that it's a straight line of wire with no bumps in it. Solder it and slide the heat shrink over.. shrink it and into the loom it goes. If you pay attention to how GM did the tape on the harness, you can duplicate it. They went around the wire at the end of the loom once, the pulled the loom into place and the tape goes through the slit..then around it to seal it up. That way the loom never slides, because it's taped to the wire and loom both.
 


Ill have to see if I can still solder worth a damn lol...last time was.....interesting. Lol.

Thanks! I will defiantly have to try it out! Lots of vac line redoing and wire re-routing to do on this car...its sort of a mess in that department.
 
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