Wires thru C5 (1998) firewall

From the inside, using the steering wheel column as a “clock”, there is a 2.5” round factory cut-out in the insulation.


You can easily pull this out of the way to drill whatever size hole you desire thru the plastic firewall. (Yes, plastic, not metal.)



I used Belden 8786. It is a shielded cable with 7-conductors (incl. the bare shield/drain conductor). It’s perfect for low amperage and signal applications such as stepper motor electronic fuel pressure gauges etc.. Used a 19/64” drill bit (almost dame size as cable) to avoid needing a grommet, then simply put the insulation back in place. Will need to splice the sending unit end back onto the original gauge harness. Easy because all the conductors are stranded.



8786 has 4 shielded wires BLK, RED, GRN, YEL and 3 non-shielded BLU, WHT, and bare SHIELD. The shielded wires are actually in a foil shield within the cable. The BLU, WHT and bare SHIELD are simply wrapped around those and protected by the cable sheath.


Tape the ends of any unused conductors and exposed shield(s). (Sorry for pic quality)

What did I want to accomplish? Getting thru the firewall ON THE DRVR SIDE of the car, shortest path possible to the end of the fuel rail. Works great and "easy to do".

Installed a couple of mini toggle switches inside the console for this and another project. Hope this helps someone.