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Ignition switch stumper

2K views 9 replies 3 participants last post by  69velle 
#1 ·
I recently had my car die on me twice. I was driving to work and all was fine, then when I left to go home it died about halfway. The drive is 20 minutes to work/home. I had it towed home and let it cool down. Later that night, I moved the ignition switch a little and it fired back up, so I thought it was just a misaligned switch. Well the next day, the exact same thing happened. I saw smoke pouring out of the hood and noticed that my wire that connects from my battery to the junction block just behind the battery was fried. I had it towed home again, but it will not start, it will not even crank over. I tried replacing the wire and took my starter down to be benchtested and it cleared.
This morning i replaced my ignition switch because as I left my key in the "run" position the wire from by battery to my junction block started to heat up really quick, and the pink wire that comes off of the top left corner of the ignition switch was getting really hot too and it is melting the plastic causing the internal connections to stick. But changing the switch did not do anything.
I suspect a straight ground somewhere because of how fast the wires get hot. But i have no clue where to look since everything is testing ok and my multimeter is showing conductivity on every wire. Has anybody had this problem before or have any ideas on where to look?
Thanks
Mike
 
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#2 ·
69velle said:
I saw smoke pouring out of the hood and noticed that my wire that connects from my battery to the junction block just behind the battery was fried. I had it towed home again, but it will not start, it will not even crank over. I tried replacing the wire and took my starter down to be benchtested and it cleared.

I suspect a straight ground somewhere because of how fast the wires get hot. But i have no clue where to look since everything is testing ok and my multimeter is showing conductivity on every wire. Has anybody had this problem before or have any ideas on where to look?
Thanks
Mike
Definitely a short to ground and a big one at that. The wire between the battery + and the junction block is a 14g fusible link. It is made to burn up and protect the rest of the cars wiring in situations like this. DO NOT replace it with a regular piece of wire as you would run the risk of frying the rest of the cars wiring and maybe the car catching fire! If you did this you may have melted other wires and will make troubleshooting and repairing more difficult. As a guess is most likely one of the main "feed" wires that is shorting, as everything past the fuse box is fused unless someone bypassed it. First leave only the ground hooked up on the battery, leave the big battery + and the wire to the junction block disconnected. For testing, use a test light between the battery + and the junction block. Light should be on. First pull the bulkhead connections at the firewall and test again. If the light still on the short is in the engine compartment. If in engine compartment you need to inspect all of the main "feed" wires. Trace the 10g red from the junction block to the 4 way splice on the drivers side fenderwell. From the 4 way splice one goes to the horn relay buss bar, one to the alternator, and one to the voltage regulator. Another wire from the horn relay buss bar ( a 16g black into a 12g red "fusible link if its still there" ), that 12g red goes to the bulkhead connection. Inspect all of there wires closely. Post back with results.
 
#3 ·
Undee,
This statement confuses me... "For testing, use a test light between the battery + and the junction block. Light should be on." I'm thinking that the light should not work, because if it does that means that the junction block is grounded and that would be my problem. Could you please clarify, or if I am not reading it right just tell me I'm dumb.
Thanks
Mike
 
#4 ·
All you are doing is replacing the the wire from the junction block to the battery with a test light. If you do not have one, get one, they sell them at auto parts stores. The junction block is not grounded, its only a connection point. Any current that flows from the battery to the rest of the car ( except the starter) has to pass through this point. When there is no short and nothing is on and everything is hooked up then the light would not come on which is what you want in the end. If you are having a lot of trouble, email me your phone# would be easier to talk you through it.

undee762@aol.com
 
#7 ·
The wires only become hot when the key is in the "run" position. I tried backward accessory and forward accessory and everything runs like it should.
Does that help at all, maybe give me something more to try?
Thanks
Mike
 
#8 ·
69velle said:
The wires only become hot when the key is in the "run" position.
Mike
I will assume you mean short instead of "hot" and its only happening in the run position and not the acc, off or start position. I only have a 1970 wiring schematic but 69s should be similar. There are only a few possibilities off the IGN switch that are not fused. One is a 12g pink. It branches into 2 wires, one feeding the fuse box the other going to the bulkhead connector for the coil. Another is a 12g brown feeding the fuse box.
If its a idiot light car a 20g brown/white strip going to the bulkhead connector which ties in with a 16g brown that goes to the voltage regulator.
The browns may be for the acc position. Maybe some else has a 69 wiring schematic that shows something different. Hope this helps.
 
#9 ·
If wires are getting warm around the ignition switch, I'd pull out the fuses and see if that stops it.
One thing to mention is the green wires get shorted to ground just beyond the RUN position. This terminal is used to test the TEMP idiot light. Something could be wrong with the switch itself.
 
#10 ·
Well, I finally figured it out. It was a bad coil, I remember having problems with the coil before, but for some dumb reason I put it back on after i switched heads. Went back to the good ole original one and it all works.
Thanks for the input.....
Mike
 
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