[1stgenbird]

I've had an issue plaguing my 67 Firebird since early June that I haven't figured out yet,


The power wire coming from the positive battery cable to a junction block sending voltage to the regulator keeps frying.


I was driving to a cruise night going across an intersection when the car lost power and smoke began pouring out from under the hood. When I opened the hood I saw that wire, which is a fusable link, had fried and the smoke was the insulation burning.


I had the car towed home and when I looked more closely, it seemed if I may have run that wire incorrectly when I recently replaced the parking lights and removed the battery to access the light connector and ground and when replacing the battery, I may have pinched the wire between the battery and the radiator and eventually caused the insulation to wear though and short out.


I jury rigged another wire (12ga rather than the original 14ga) by crimping a ring terminal on one end to attach to the junction block and stripping an inch of insulation off the other end and sticking it under the positive battery terminal. Problem solved, or so I thought.


Car drove fine for a week or so then it happened again, 3 times in the span of 10 miles. Someone suggested replacing the voltage regulator as it may have been damaged when this initially happened so I did. Again drove fine for 10 miles then happened again last night right in front of my home. Replaced the wire and it instantly fried, tried again and fried. I was just trying to get it started to make it back into my garage. On the 3rd try it worked and I pulled into the garage.


I put a voltage meter across the battery and it read as it should have once it was in the garage.


I'm stumped. I have to say that all the wiring harnesses in the car were replaced last year with ones from AAW.


Any thoughts?

[Lee]

For the wire to burn, it has to have more amps going through it than what it can handle.

The main wire burned, and the fusible link did not blow?

What else is connecting to the "junction block" you mention?

Maybe draw a diagram of your wiring.

[rwfisher]

Obviously drawing allot of current.. Measuring voltage across battery won't help isolate. You will need to measure current and start unplugging components until you see a big drop in this case. By the severity it sounds like you have something that is going right to chassis ground or shorting out completely.. I would first determine if the engine needs to be running or not for it to happen (High current reading) or if only when starter engaged or ignition in On position. Shorted starter can draw a ton of current.. At this point I'd do all the testing in the driveway and have an extinguisher handy because you've been lucky so far.....

[1stgenbird]

This is the circuit diagram with the arrow on the wire that fries. I see nothing visually such as bare wires, that may be the cause.

[HWYSTR455]

It's got to be a short to ground on the wire that runs to the horn relay.

EDIT: Or possibly on the other side of the horn relay. But it most likely would be a to-ground short.

.

[johnta1]

1st, have you added any extra electrical accessories?
(big radio amp, etc)

The wire from the battery to that junction block is the only thing that 'smokes' and gets hot?

Have you checked the wires from the junction block to the splices that go to the alternator, regulator and horn relay?

If it is just the wire to the junction block from battery, I'd change that or at least look at it closely.

[HWYSTR455]

Oh. Well, yeah, make sure youre using the correct gauge and quality wire for that run. Horn relay basically powers everything inside the car, right?

[bill ryder]

Is the junction block mounted to metal like firewall or inner fender?? If so, take it loose and see if problem goes away. JB may be shorted. I'm not a firebird guy.

"Bill"!

[1stgenbird]

Turns out the alternator was bad. I just happened to notice sparks coming from the back. Removed it and a burnt wire and diode fell out.

[HWYSTR455]

Overcharge. Guessing you don't have a volt gauge? May consider adding one.

Also, just to say, you should only run GXL or TXL grade wires in the engine bay. The crappy auto parts store 'primary wire' doesn't hold up to any kind of higher heat.

.