Truck starts, runs great, but wont TURN OFF...

[MarineCorpsMP]

My truck- 1972 Chevy C20, 2WD, Automatic, 350

So my brake lights stopped working the other day and I decided its about time to replace all my fuses (brake fuse was blown). Well after i replaced all the fuses... my truck started right up (as always) runs great, but then the stumper....


I can turn the key off, pull the key out, and my truck still runs and drives as usuall, no change in how the truck drives at all. I have been turning the truck off by unlpuging the UNFUSED wire that goes to the distributor.

And just for one more kick in the groin... my brake lights still dont work.

Any ideas?

[*Dylan]

Well I'll start off by saying you have an absolutely beautiful truck! Try using the search button in the top of the forum, there was someone else that had a problem like this at one point. I would do it and try and find it for you but it seems search isn't working for me. Good luck getting it all worked out!

[vegaschevy]

I would say that your ignition switch probably has a short in it. Not real sure, ill do some research on the other person who had this problem

[Classic Heartbeat]

It sounds like you are running an HEI ignition. Where is the other end of the wire plugged in at. The 12 volt source should be the ignition unfused plug in the fuse panel or the resister wire cut out of the harness and replaced with a standard wire. The problem with your brake lights could be the brake switch at the top of the pedal assembly. WES

[hayhauler71]

Do you run a hei dist. and make sure it is wired only hot with key on or crank position.

[mclairmo]

Make sure no starter wires are touching each other.

[MarineCorpsMP]

Sorry should have said it has a Delco-Remy HEI.

Classic Heart Beat,

Yea the 12V source is in the Unfused in the fuse block, and it runs straight to the HEI. Pics attached wire from firewall and where its plugged into the HEI.

After searching the internet i found another message board where a poster said he thought it was "Alternator Feedback" but did not elaborate on what exactly that was, how it happens, or how to stop it. Anyone know more about this?

Man I hate it when I get stumped.

The only reason why I think it may be fuse related is because I never had that problem untill I replaced the fuses. 20A fuses brand new from autozone.

Hmmm....

[Tynee]

Don't have any idea if its related or not, but I have a short of some kind in my headlight switch, so if it's in exactly the right spot, I can do exactly what you've described, turn the key off and still get power to the electric fuel pump and ignition system. As soon as I turn off the headlights, it goes away. I could (and probably should) replace my headlight switch to see what that does tot he issue, but It hasn't really botherd me enough to care, yet.

So, I guess that was a long winded way of saying that it probably doesn't apply to you, but the PO may have hacked into your headlight wiring somehow.

Edit: If you scroll further down the listing of forums, there is an electrical forum. I bet there's somebody in there who would be more help...

[MiniD]

You're getting 12v to your ignition at all times. I know it's painfully obvious, but the "unfused" wire is connected to a terminal with several fused wires. You'll want to start pulling the fuses one at a time to see where you are getting the 12 volts from. Then, work your way back from there. There actually should be two fuses that cause this problem to go away... the fuse providing the 12v from the non-ignition terminal and the fuse providing the path back to the terminal the ignition is connected to. Stuff like this always seems to be caused by off the wall things like clocks, backup lights and neutral lockout switches just because those are 12 volt supplied lines that are seldomely noticed as being a problem if they're not connected right.