The ballast resistor limits voltage to the coil during low speed operation but allows voltage to rise as the engine speed increases. While the engine is cranking the resistor is bypassed to give adequate voltage to the coil for starting. This is accomplished by a separate wire to the coil side of the resistor that supplies battery voltage only when the switch is in the crank position. (You will not get 12 volts at the coil unless you are cranking the engine or are operating at higher speeds.)

 

Ok I'll check today and let you know.

 

I have 12v at the red wire side of the ballast resistor... is that right? If not, would it be the voltage regulator?

The ballast resistor is also hotter than the surface of the sun when the key is ON. How hot are they supposed to get?

 

The resistor can get quite hot. One side of the resistor should have 12 volts with key in run position. The other side should have less than 12 volts with key in run position. Both sides should have 12 volts when key is in the start position. If not, the problem is in the wire or ignition switch system that overrides the resistor to give a full 12 volts for starting. What is the resistance reading of the resistor?

 

I think I have deeper problems than I thought.

Looks like the wire that goes to the starter relay/ballast/coil is smoked. I knew the ballast was getting too hot but didn't realize I had that bad of a short.

The truck has been fine for a year and I wash the engine (which I've done many times due to a leaky radiator overflow) and now it's totally dead.

I don't even think it's fixable... unless of course I paid someone to trace every single wire and make sure nothing else is fried, then rewire everything.

 

Those wires are salvageable without having to remove them. Get a can of 3M Scotchkote part number 054007-43906. It is a brush-able liquid insulating compound that is great for fixing frayed or cracked insulation on wires. It resists moisture, oil, and hydrocarbons. I have never had a repeat problem with any wire I have used it on.

 

Yes but I think the wire is melted through the entire harness. I'd have to peel back the tape on the whole thing.

 

The hard part of the problem is over (the trouble shooting) and the fix is not difficult just messy and time consuming. Once the tape is removed you can stop thinking and know for sure how extensive the damage is. Replacing a few wires is easy. The tape can be replaced with flexible wire loom. None of the other alternatives at this point are very attractive unless you are thinking of just scrapping the truck which seems a bit extreme over a bad wire or two.

Grab a six pack and a sharp utility knife and dig in. If it requires a second six pack grab some band aids too. LOL