Electrical Problems Arrgh

[elonblock]

Also make sure that the holes where the fastener attaches to the sheet metal are bare metal and have a good bite. And doesn't have a thin coating of paint insulating the grounding fastener.

This is critical especially if the car was touched up or restored in the engine bay with fresh paint.

It only takes a thin coating to insulate the fastener and seek a ground elsewhere as was mentioned previously.

I ended up welding up the holes in the firewall and redrilling, because the holes were oversized and the screws were basically a slip fit.

It can be a real hair puller!

[Ngtflyr]

I will be rechecking all the engine ground straps, and will be adding the ground strap to the passenger side frame to inner fender well. Looked at another car today that has one there. My car definitely never had one in that location but will tomorrow. All the ground straps are well illustrated on page 439 of the assembly manual as well. I will let you know if those fixes solve this PITA.

[Ngtflyr]

Well I am back on it after being gone a couple weeks for work. Still blowing the turn signal fuse, but only if the radio fuse (the one above the turn signal fuse) is in. If the radio fuse is out all is well. I have added an additional grounding strap that my car never had to the passenger front frame to inner fender well. Rechecked all the ground wires under the dash as well as the firewall and frame grounding straps. Replaced the flasher. If I unplug the radio wire harness the turn signal fuse still blows. Feel like I am a dog chasing it's tail. I have noticed I hear a click under the dash somewhere about the same time the fuse blows.

[PxTx]

Sounds like you've got a dead short if there is a click just before the fuse blows. It has been a while since I've been through the wiring in these old cars. Is the cig lighter on the same circuit as the radio?

I would install the radio fuse and then grab a multi-meter. Put one lead on the negative batt terminal and start checking your leads on the turn signal circuit. Repeat on the radio circuit if nessisary.

You'll be looking for stray voltage. Ideally you'll have 12 volts on the positive terminals and 0 volts on the grounds. If there is less than 12 votls on a positive circuit or more than 0 volts on your grounds then I would look more closely in that direction.

Since it blows the fuse repeatedly you are actually in a good position. Figure with the radio fuse out, one of the power leads is just and open wire, fuse-in is providing power to the shorted area. The short is occuring when there is power being supplied to your turn signal ground(s) I suspect. Now that I type that, I'm thinking it's the other way around with the turn signal power shorting over on a radio ground, since it is the amps on the positive side which is blowing the fuse.

Again, I'm unclear in the specifics of these old harnesses. Can anyone else clarify things better? Am I going in the wrong direction?