1969 Dash wiring issues?

[DeadStang]

I've had this car for awhile, but it was out for paint and so recently back "home" and is now being driven. Initially, I noticed that the gas and temperature gauges would die for a minute or two, then come back and everything would be fine. On Wednesday, the radio went out and then came back on in a minute or two...I thought maybe a loose wire (it's one of those groovy new stereos that look vintage but has an MP3 or whatever hook-up). Then, driving the kid to school this morning, the radio died, the gauges died (the tach and speedo aren't affected), and the heater motor didn't just cut out, it kind of ran down and I quickly turned it off as I noticed a burning wiring smell(!!!). No smoke noted and the gauges came back on and the blower motor came back, but I'm tweaking about this.

Could this be as simple as the ignition needing to be replaced, or something worse? I was thinking the ignition initially, but the hot wiring smell now has me worried...

 

[AzPete]

Old harness........send to Midlife for refurbishing and possible location of problem. Check all items while waiting.

New harness......stand on your head and start looking for burnt wires. Then start fixing the problem.

You really need to find the bad wires to see what system is being a problem.

 

[DeadStang]

Old harness........send to Midlife for refurbishing and possible location of problem. Check all items while waiting.

New harness......stand on your head and start looking for burnt wires. Then start fixing the problem.

You really need to find the bad wires to see what system is being a problem.

One of his refurbished harnesses was installed when the dash was out for cowl work. That's why, initially, I was thinking just the ignition cylinder...

 

[AzPete]

OK....stand in your head and locate the bad wires before you throw parts at it. Also, contact Midlife about it.

 

[Midlife]

Hi there Kim, and I'm sorry you're having problems. Your initial symptoms, before you mentioned smelling smoking wires, sounded like a bad alternator, and running solely on the battery. I still would check that first. If your alternator wiring got fried, there are some paths for feedback from the VR to under the dash. Plan B...

Where did you smell the smoke...inside the car or under the hood?

Inside the car, power comes from the firewall connector to the fuse box, ignition switch, and headlamps directly from the battery. Everything else is fused. Accessory power is converted at the ignition switch, and some headlamp functions are converted at the headlamp switch. I would also carefully check for the grounding point for the harness under the dash; with a newly painted car, sometimes the paint prevents the ground from working correctly. Unfortunately, it sounds like you'll have to disassemble things to find the source of the problem. If anything is wrong with the underdash harness, just contact me for a FedEx account number, and I'll fix whatever is wrong at no charge, whether it was my fault or someone else.

 

[DeadStang]

Hi there Kim, and I'm sorry you're having problems. Your initial symptoms, before you mentioned smelling smoking wires, sounded like a bad alternator, and running solely on the battery. I still would check that first. If your alternator wiring got fried, there are some paths for feedback from the VR to under the dash. Plan B...

Where did you smell the smoke...inside the car or under the hood?

Inside the car, power comes from the firewall connector to the fuse box, ignition switch, and headlamps directly from the battery. Everything else is fused. Accessory power is converted at the ignition switch, and some headlamp functions are converted at the headlamp switch. I would also carefully check for the grounding point for the harness under the dash; with a newly painted car, sometimes the paint prevents the ground from working correctly. Unfortunately, it sounds like you'll have to disassemble things to find the source of the problem. If anything is wrong with the underdash harness, just contact me for a FedEx account number, and I'll fix whatever is wrong at no charge, whether it was my fault or someone else.

Something else I forgot to mention--that may or may not be relevant. Mid, you've been to my place...I have the little drive a few miles into town. The weird stuff never happens on the drive it--it's always when the car is nice and warm and has been on the road for at least 15 minutes.

The smoke smell was when I was driving to work after dropping the kid off at school. It wasn't strong and there was no smoke visible anywhere inside, or rolling out from under the hood...but I suppose it could've come from underhood and drifted into the cab. So I guess the answer to that question is, I'm not sure.

I wasn't really thinking this was the harness itself, since the issues seem to be somewhat related to each other--and all seem to revolve around the ignition switch (I mean, the #2 gauges, radio, and heater motor go off and on with the ignition, right?). Also, the wiring is "new," but the alternator is some old, chromed thing that came on the motor that was in the car when I bought it, 4 years ago.

The weather is supposed to be good here for the next week and I want to enjoy what little Mustang weather I have left, so this shiny green thing is going to have to sit in storage while I drive something else, since I would rather it not catch on fire on the way to school. I'll re-visit this issue in a week or two.

Since I'm generally a crappy mechanic and I tend to diagnose things by throwing parts at them, what do you think about me tossing a new alternator, the little alternator wiring harness, and ignition switch at it and see what that does? I am feeling nausea tonight at the thought of pulling the dash and getting at the harness back there.

 

[Midlife]

Your plan sounds reasonable to me. You likely have a couple of alternators laying around, and the alternator subharness is inexpensive. When you install the ignition switch, look carefully at the connectors for signs of heat stroke!