I am getting close to finishing up the complete restoration of my '73 Road Runner. All of the wiring harnesses were replaced with brand new M&H harnesses where available, and unavailable harnesses were reconstructed with new wires to the same specs as OEM or better. I triple checked everything and had all connectors labeled for proper placement when installed. The only changes were bypassing of the AMP gauge and conversion to a Volt gauge (
MAD Electrical). All of the relays and switches were replaced with new or NOS. I also converted to LED panel lamps to reduce the electrical draw on the system. I installed the dash harness in the dash before installation into the car to ensure everything was connected right. Bottom line, I did everything I could to ensure I didn't have any wiring issues.
Last week when I finally turned the key to start the car and test out the electrical system, I had no panel lights and the 5A fuse (the only 5A fuse in the bulkhead, top right cavity) blew almost instantly. I replaced the fuse and had the same result. I also had a smell of hot wires and light smoke start to come from an unknown source behind the gauge cluster. The headlights and front marker lights worked fine (rear lights are not installed yet), the brake light on the dash worked, the manual reverse light worked, the horn worked, and the ignition worked to activate the starter. I removed the dash and inspected the wiring harness, but could not locate any source of the hot wires or see anything pinched or damaged.
Thinking that it was possibly a bad chassis ground, I spent today running a 10 Gauge wire from the ground wire on the radiator support directly to where I have everything grounded behind the dash. When I tried everything today, I had the same results except the headlights didn't work. When I would attempt to put the 5A fuse into the bulkhead, it would blow before I could even get it snapped in place. I tried to bypass the fuse to see what would happen and I had smoke and a hot smell coming from the area of the headlight switch connector almost immediately.
Where do I go from here and what can I try to get things working? I have yet to see the panel lights work and now the headlights aren't working either. The headlight switch is brand new and I didn't do anything to modify the plug or connector for the headlight switch on the new harness.
Sorry for the long post, thanks for any suggestions or help.