Puff of smoke (electrical)... now car won't start

[HughDTX]

First post here. I did a search ... found nothing of help. I will try to keep this short.

First off, I have a 1972 350 Coupe.

I replaced a front side marker bulb and a rear side marker bulb today. The old bulbs had no writing on them so I had to hold them next to the ones at the store and I found that only one set looked like em (12V 2825 W5W). I realize now that I should have got the 142, after I pulled another marker bulb and it did have the part no. written on it. So, in short, I put the wrong bulb in. I realized it too late I think though.

Before I realized they were wrong I plugged them in and turned on the lights (w/out key). Everything lit up great... front and back. So I assumed I got the right thing. Turned off lights.

Minutes later, I was gonna do something else so I got in the car to move it a couple feet, so instead of actually starting it I put key in first turn and put car in neutral pushed it and then gone back out. My garage smelled of smoke. There was a white smoke in the air coming from the engine bay. I popped the hood and followed the smell to my alternator and/or a spool next to it along wall of bay. I did not turn the lights on at all during this time.

Now my car won't start... no lights... nothing (accept after market alarm that taps into battery... been there for years).

Any ideas?

I looked around and couldn't find wires burned. I am thinking the alternator called it quits or there's a melted wire I can't see. How can I determine if a wire is bad? From what I can see everything looks the same and looks good, so I think the inside of the alternator burned and created a white smoke.

Now, what caused it? Could the two little bulbs have done all that, even while being off!?

THANKS!

 

[HughDTX]

Ok... I don't know a whole lot, obviously.

Couple more questions:

Could a bad alternator keep the car from having any power anywhere even when no key is in ignition?

Are there any in-line fuses I should look for? I couldn't find any, and I couldn't find any fuse box. Where is it?

Because there was smoke I assumed it was something more than a fuse, as it wouldn't smoke, correct?

 

[The73vetteman]

Hello Hugh,

Let me be the first to welcome you to the CAC.

I wish I had something useful to offer you, but all I have is this paper on electrical problems.
Enjoy!

 

[MaineShark]

It may be a fusible link, which is basically a piece of wire that melts at a predictable load. It serves the same purpose as a fuse, but it is harder to replace. I believe the idea is to encourange people to take the car back to the dealer or a mechanic for service.

I'm not certain about your '72, but I wouldn't be surpised if there was a fusible link somewhere between the starter hot terminal (where the battery wire connects to the rest of the car) and the main electrical system. I also wouldn't be suprised if the link was near the alternator.

While there would still be power getting to the starter, there wouldn't be any power to the ignition switch, so there would be nothing to trigger the starter.

Best bet is to find a wiring diagram for your car (a Chilton's or Hayne's shop manual should include one), and track down where the link might be.

You can start by using a voltmeter to measure the voltage at the starter's hot terminal (red lead on the terminal, black lead on a good clean ground, such as a clean spot on the block or starter case). You should have somewhere between 12 and 14 volts there. Next, check the main power connection on the alternator (or does the '72 have a separate regulator?). That should help to eliminate any issues with the wiring between the battery and the car, so you can focus on the wiring past that point.

Joe

 

[HughDTX]

Thanks a ton for your help, guys!

I am going to inspect the loom I think smells suspicious more tomorrow. I just went in with a clean nose and the alternator smells fine. Plus, I dont think the alternator's malfuction would hinder anything else from turning on.

OH, and one other bit of important info I just realized.... the horn still works, so the car is receive some power, somewhere.

 

[Enigma]

Just my 2 cents worth but the Alternator shouldn't stop the car from starting.
I would check the starter circuit that consists of the starter solenoid, fuse, ignition switch,battery,and starter motor. The starter solenoid mechanically engages the starter motor and eletrically closes a high current switch that connects the starter motor directly to the battery.

Good luck

Enigma

 

[MrGibbly]

I had a similar problem after replacing my alternator a few days ago. I had somewhow managed to burn one of the fusible links that is connected to the hot terminal on the starter. I would check those as well as all of the fuses in the bus (below hood release in cabin). If it isn't one of those things just start working your way slowly from the battery terminals to the end of each wire run with a voltmeter and see where it goes dark.

 

[Enigma]

One other item popped into my mind since you said you put it in neutral and pushed it.

The neutral safety switch (automatic)(located in the center consule) or clutch start switch(manual) my be the problem.

Enigma

 

[HughDTX]

Ok... I found a wire that was groudn near the alternator. It was melted so I fixed that. Now car starts up great.

BUT

Headlight motors don't work now (although headlights do work)... and passenger front turn signal and side marker are out (I think bulbs are burned though)..... anyone know what could cause motors to not work? All the wiring I could see looked fine.

Thanks!

 

[MaineShark]

Unless someone has done some customizing on your car, the headlight actuators are vacuum-operated, not electric. So that means checking for proper vacuum signals.

I'm sure someone could walk you through it.

Joe