1972 Satellite light problem

[66Sprint200]

Hey guys, sorry that I haven't been on in a while. The Satellite's rally gauge conversion was a success... for a while.

We did the conversion in November, and everything worked great, working gauges, working lights, working car. But last week something happened. We're not sure what happened, but here is the new problem.

The car runs fine without the lights on. But when you turn them on you will hear the engine seriously bog down, and then all the lights (except for headlights, turn signals, and brake lights) go out. It blows the 20A misc. fuse, and I mean to the point that the glass cracks. Once the fuse blows and the lights go out, the engine idle bumps back up and the car runs fine.

I checked the voltage regulator to see if the alternator was overcharging, but it wasn't. Any other thoughts on what it could be? Thanks guys, Michael.

 

[72RoadrunnerGTX]

Short circuit in the dash illumination or running (parking) light circuits. The “MISC” fuse protects the “BAT2” headlamp switch power feed. Something less than a dead short or the fuse would blow instantly.

 

[66Sprint200]

So maybe a wire up in the parking lights has started to break off it's insulation. I'll check all the wiring see if any of it is exposed and shorting out (good possibility with this car). And the lights will only stay on for about 4 seconds before the fuse gives out.