Passenger firewall plug pinout

[Thenameless]

Onto another issue.. and looking for some much appreciated help. I was quite eager and foolishly cut the passenger through firewall harness and removed it from my harness when ditching the 4.3 for the 5.3 swap. I have been messing about with grafting a stand alone harness ever since. The truck runs well, most things work but I'm looking to reinstall that harness through the passenger side to get my heater functioning again. I have not been able to get my tach to work with the white wire coming through the driver side plug either. (Tried 1k resistor) Verified signal with an aftermarket tach and my signal wire from pcm works as it should. Volts on the dash doesn't work, and fuel gauge has me stumped too. I have put a fuel gauge on the pillar pod that works but I want that spot for boost controller now if anyone has a pinout or diagram for the few wires that come from the passenger side harness that would help alot. Thanks again.

 

[Schurkey]

You're posting in the '96+ "Vortec" section, but beyond that we don't know WHAT VEHICLE you're dealing with.

Download the service manual set for your vehicle from the links in the sticky section of this forum. Your answers are in there.

 

[Thenameless]

Its a 98 c1500 reg cab shortbox. Was 4.3 manual. Now its 5.3, 4l80 14 bolt. I will see if I can navigate through the manuals. Thanks.

 

[Thenameless]

I'm a little embarrassed to admit that I can't find the info I am looking for in the manuals. If there is anyone who can let me know which colors are what I would send over a digital case of beer for their hassle. The wires are cut on the engine side with enough there to graft on new wires.

 

[Thenameless]

I'm a little embarrassed to admit that I can't find the info I am looking for in the manuals. If there is anyone who can let me know which colors are what I would send over a digital case of beer for their hassle. The wires are cut on the engine side with enough there to graft on new wires.

Hopefully thats not against the forum rules.

 

[Scottm]

On my 97, the purple wire in that bunch is the obd2 port serial data wire going to the ecm. Mine also had two chassis grounds plus several wires going to the transmission for the gear indicator lights. The chilton manual for the 88-98 trucks have pretty good wiring diagrams. Also there is a reference section on here somewhere that has a 98 factory service manual you can download.

 

[Thenameless]

On my 97, the purple wire in that bunch is the obd2 port serial data wire going to the ecm. Mine also had two chassis grounds plus several wires going to the transmission for the gear indicator lights. The chilton manual for the 88-98 trucks have pretty good wiring diagrams. Also there is a reference section on here somewhere that has a 98 factory service manual you can download.

Thank you. I did find 2 grounds and a red positive for the heater motor. There was also a module for the fuel gauge. One for tcc lockup and another for ground to instrument cluster. Long story short, I grounded the 2 negatives behind the glove box, ran the power wire across inside the cab and out to the fuse block to the heater fuse (50a). The rest of those wires are in tye garbage now and there is no use for that plug. My trans is already hooked up to pcm with new wires, and fuel gauge sender had a new wire previously too.

 

[GoToGuy]

Next time do a little research, have a plan , don't burn bridges before you've won the battle.