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1997 GMC W4 O2 Sensor Wiring

  • HarryL
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06 Jul 2019 13:49 #31459 by HarryL
1997 GMC W4 O2 Sensor Wiring was created by HarryL
I have the same 1997 5.7L V8 GMC W4. The issue I am faced with is that O2 sensor J110 and J111 in the attached diagram will blow fuse F16 when power is applied together. Power line black and red had melted in some areas and I had to replace part of the line. Even if I try to split the power line, it will blow the fuse. If I run 1 red and black line to 1 of the O2 sensors, it works. The readings I got from back probing J110.

Pin 1, Black: .10V
Pin 2, Green/black: 0V
Pin 3, Black/Red: 12.34V
Pin 4, Green/Red: .08V

Any assistance in guiding me in the right direction on how to figure this out will be greatly appreciated.

Attached is a copy of the wiring diagram.

I hope I don't sound to confusing in trying to explain the issue.

Thank you.

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06 Jul 2019 14:26 - 06 Jul 2019 14:29 #31461 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic 1997 GMC W4 O2 Sensor Wiring
The damged wires you repaired may be effect rather the cause, my first move would be to remove the fuse and disconnect all four sensors.

(1) Simple resistance ohms test between red-brown wire and ground.

the fuse out and everything disconnected you should see very high resistance.

If the resistance is low then you have a short in the actual wiring.
There are techniques to locate the position of shorts in wires but for the non-tech eyes and touch wiggling the wires are the way to go if that dosn't help it is really case of actually making a cut or cuts in the wire to locate which section the short is in.

If the resitance high indicating the wiring insultion is intact you may have a short internal to one of the sensors.

(2) Resistance check on eacthe h individual sensor heater.

" Welcome to the 21st"

Last edit: 06 Jul 2019 14:29 by Andy.MacFadyen.

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