Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
Hello. Welcome to Just Answer. Please allow me to assist you. The best way that we have found to run wires thru the firewall is as follows:
Locate an area on the firewall that does not have wires on the other side, and is accessible form inside the cabin.
Using a 'step' drill bit (this is a drill that drills a bigger hole the further it goes into the hole being created.
Get a common rustproofing body plug from a parts store
Drill the hole with the step bit to the exact size of the rustproofing plug
Paint the bare edges of the hole to reduce rusting.
Cut a hole into the middle of the body plug and run your wires thru it
Pop the body plug into place and seal with some RTV or similar sealer.