I have no doubt in my mind that this most recent failure of my 71 Cutlass was my fault but it really threw a wrench into my best laid plans.

About three weeks ago the I was attempting to start the car to leave work, it didn't want to idle cold and kept stalling out (350 rocket lightly modified, turbo 350 trans, holley street demon carb with electric choke). After three or four attempts and gentle application of throttle the car was warm enough to stay running, however the blower fan stopped working entirely. I checked the fuse box and the heater fan fuse had blown. I then drove it home, experienced no new problems, and parked it in the garage. Once it had cooled some I set about adjusting the timing and carb to achieve a better idle so it would run better on cold starts.

The next day I picked up some 25 Amp bus fuses and replaced the blown fuse for the blower motor and it kicked on perfectly. Two miles farther down the road the entire engine compartment was smoking from everywhere and the wiring running down the driver's fender was on fire as well as the AC harness, horn relay, AC control relay, transmission kick down cable was glowing, and ground straps were smoldering. I had a fire extinguisher with me and some pliers so I cut the positive connection from the battery to the horn relay and put out the smoking glowing wires with the fire extinguisher. There was no fire damage to the car except for a melted hole in the plastic fender liner on the driver's side (thank God) and the burnt wiring seems contained in the front lamp harness, AC harness, and positive battery cable.

I have ordered replacement ground straps, new harnesses from American Autowire, and new relays to replace the two crispy fried ones.

I will be installing everything this coming weekend that I have ordered (AC and front lamp harness), but should I be looking further into the system than I already have? It seems like the car tried to find a ground through a short to the fender from the positive cable and possibly was using the transmission kick down cable as well. Will new cables, grounds and harnesses stop this from happening again? The fuse box and all the wiring inside the car seem fine, the only places that burned were in front of the firewall in the engine compartment but it seems to have started when I replaced the blower motor fuse in the fuse box.

 

I'm sure my opinion will be argued against by some but I'd opt in favor of caution by replacing the dash harness as well. Pricey endeavor, but you can usually get a 20-30% discount when Year One runs their weekly or monthly sales and it's good insurance against the possibility what you can't see inside your old harness may still be another problem waiting to happen as a result of the residual failure.

This assumes you're able to determine the source of your original failure so that the underlying problem(s) can be fixed on the surface, to avoid a repeat incident