Printable View
Im starting to modify my 04 5.3l harness for my swap in my 67. I have the pinouts. Theres lots of wires i know what they do and a few i have no clue what purpose they serve. Is there anywhere that explains the actual function of each wire. Like the ones labeled "low reference" or "axle switch signal" for instance. Any help is appreciated, Kyle
Give us PCM pin numbers or circuit numbers and we can help. Also have to know what the donor is.
Its an 2004 5.3l chevy avalanche harness,
Pin Color Circuit No. Function
Blue Harness
21 YEL/BLK 1868 Low Reference
23 BLK 470 Low Reference
25 TAN 1671 HO2S Low Signal - Bank 2 Sensor 2
26 TAN 1667 HO2S Low Signal - Bank 2 Sensor 1
38 PNK/WHT 1101 Damping Lift/Dive Signal
Green Harness
19 BLK/WHT 1695 Axle Switch Signal (NP2)
74 LT GRN 3212 HO2S Heater Low Control Bank 2 Sensor 1
Thats pretty much it. Alot of the ones i wrote are in the harness 2 or 3 times, but i really dont know what they do, Kyle
25 goes to terminal A on the passenger side rear O2 sensor.
26 goes to terminal A on the driver's side rear O2 sensor.
38 goes to connector C3 terminal A1 at the EBCM.
19 is pink IGN1 voltage on the blue connector....not BLK/WHT axle switch signal. The circuit you posted on 19 is in the green connector and is only for 4WD with NP2 transfer case and the Av didn't come with that T/C.
74 on the blue connector is not what you listed.....it's supposed to be yellow ECT sensor signal. It's the green connector that has the 4 LT GRN 3212 HO2S Heater Low Control Bank 2 Sensor 1 that connects to terminal C on the passenger side front O2 sensor.
Thanks gasguzzler, i put green harness in my post, prolly should have put it in bold lol
Hahaha I thought that was part of your description of the circuit above. Do the ones I commented on make sense?
Are the ones that say low reference required?
Yes they make since, i figured those were part of the 02 sensors but wasnt positive
get on alldata.com and buy the online support for the donor vehicle, it'll have every pinout and connector you need to identify.
Thanks ill get on it!
Alldata won't tell you were something goes just by knowing the circuit and pin numbers though.
The low reference wires are important for sure.
21 YEL/BLK 1868 Low Reference goes to terminal B at the crank sensor.
23 BLK 470 Low Reference goes to fuel tank pressure sensor terminal A. The only way to find these is to look for the pin number and circuit number in all the PCM schematics....finally found all the pics.
Hmm i never thought about the pcm schematics
Where might i be able to find the schematics?
I know there are some publishers you can buy online info from. Try AllData and Mitchell on Demand.
Thanks!
Their schematics aren't nearly as good as GM's but at least you have access to them all the time.