Ok, so this can be added to the long list of fog light questions. Anybody know how to unplug and disassemble the C100 firewall connector? I don't want to break it and I need to get inside it to add the fog light wire/terminal. I made my own harness to the lights out of a partial OEM harness so just need to figure out how to get the wire into the firewall connector. All the dash wiring was already there and I added the switch, relay and fuse.

Also, anybody know if the ground gets picked up inside the C100 connector or does it just run to the firewall and get screwed down there? It looks like the TPI harness that you can buy aftermarket grounds close to the light. The OEM front piece of harness I used didn't have the ground there and looks like it ran back into the engine bay light harness...

Thanks....

 

It's been awhile since I've taking mine apart, but I believe there is a nut in the center of the connector that keeps both sides together. If you remove that, it will become 2 halves. Is that what you mean?

 

Something like that... It looks like you have to disconnect the two halves or at least the front lighting side and then pull it up to get at the back cover clips and slide it down the harness to get at the wire connectors to add the fog light wire. Does that sound right?

 

There is a small bolt in the middle of the connector you need to remove. It's an odd size, like 7/32 or something goofy like that. You unscrew it, then pull the entire C100 plug out. Remove the plastic shell on the lights side, then there is a small white or blue plastic retainer that needs removed from the side of the plug. Use a tiny flat screwdriver, like from a small electronics toolkit to gently pry the retainer out. Its fragile so be careful. It has long fingers that insert between the rows of contacts to keep them in place. You'll then see the stickiest, nastiest stuff GM ever created sealing the plug against water. Use that same small screwdriver to scoop out as much as you can. Soaking the plug in lacquer thinner will help dissolve that stuff. Then find an open pin location and insert your wire. You'll need to remove 2 nuts that retain the interior half of the C100 from the engine bay side so you can push the connector back into the cabin to insert the inside half of the wire to the foglight switch.

 

Thanks for all the info.. I will probably try to pull it apart tomorrow night... I have the factory harness in the dash for the fog lights so I just have to find the right terminal for the front fog light harness to add to the light harness connector in the engine bay. I won't need to pull it apart between the front and back of the firewall, just the plug in connector on the front harness portion... Just couldn't figure out how to get the front light harness unplugged so I could pull it up to open the backshell on the connector.