Hey Guys...

Can someone provide me the wire colors for each wire for the C3 connector pinout on an 88 Fiero GT? I have the pinout map...but im not sure which colors correspond to each pin.

*Context* a machanic removed my broken stock fuel gauge and replaced it with an aftermarket one...he accomplished this by cutting into the C3 harness and wiring in a custom harness to the after market gauge...Im looking to hook back up the stock gauge now that its fixed, and then put the wiring harness back to stock.

Don't know if this helps:

[This message has been edited by IMSA GT (edited 07-08-2025).]

While you're in there, it would be a good idea to do the temp gauge fix if you haven't done so yet!

quote While you're in there, it would be a good idea to do the temp gauge fix if you haven't done so yet!

Fiero Focus Coolant Temperature Gauge Wiring Repair
https://www.fierofocus.com/...osails/tempgage.html

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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

There is a better way to effect the wire swap for the temp gage that leaves the engine wiring untouched.

1. Snip the wires on the ignition switch at terminal G (lt grn) leaving enough wire to attach the snipped wires from the gage together to complete the gage circuit. (This removes the ground that causes the TEMP gage to peg)

2. Add enough wire to the snipped wires still attached to terminal G to reach the HOT lamp circuit at terminal 13 on the instrument cluster plug C3.

3. Snip the wire from plug C3 terminal 13 (dk grn) and attach one jumper wire to each snipped end. (This will provide the ground path to allow the HOT lamp to illuminate in the BULB TEST position)

This wiring change does not affect the engine wiring and eliminates any confusion when troubleshooting engine wiring in the future.