Truck dies if you let off key??
 

Just wondering if anyone else has ran into this problem. Truck starts and runs long as you keep holding the key turned meaning starter is still engaged. Soon as you let go looses all power and dies. I have tried diff ignition module but have the same out come. So I ran a power and ground straight from the battery and everything works.... So before I take the time to go freeze pulling out my spare ignition switch I thought I would ask for some advice? Im just having a hard time to believe that there would be a short. I have looked all the wiring over and can't find anything and there were no problems with the ignition switch when I had the 302. But knowing this truck anything is possible.

Thanks for your time

I had the same problem when my truck build came to the starting the engine part of things. I had some wiring in the wrong place in regard to the solenoid (I think). It's been a while back now.

You have a short in your key on run or a short in your ignition switch. Try jiggling the wiring behind the ignition switch first.

I had the same issue, the P.O. had a three way splice in the key on run wire. It split the wire and shorted. I hate splices. Always use solder and shrink wrap.

Sounds like either the wiring at the switch or the switch itself. They make a constant ignition contact in either run or start and it sounds like it isn't contacting in run.

Look for a 3 wire plug about the center of the firewall. It will have a white w/ red trace, red w/ white trace and a red w/ green trace wires. Unplug the wire. With the ignition "on" check for voltage at the red w/ green trace wire. If there is no voltage, either the ignition switch is bad or the resistor wire has gone bad.

What Mike said...
That's the classic symptom of an open circuit in the ballast resistor, or in this case the resistor wire, which serves the same function.

Good luck,
Karl

Thanks for the help guys. When I get back out in the shop tomorrow ill check those things out and let you know what I come up with.

Ignition switch, very common as they get older.

Had the same problem on my 79 and it was the switch. I took it apart and cleaned it. The truck was sitting for a few years when I got it, been working fine ever since.

So my parts truck had the wrong switch. I finally picked up a new BWD one at Orielys and when I went to plug it in couldn't get the connector to snap in nicely. so I used a little more pressure of course chipping a chuck of the outer plastic off but it plugged in and now when I try to start it it just clicks. So I through the old one back in and it starts just don't stay running. I checked all my wiring with power probe everything checks out good. So I'm just wondering if you guys have experienced the same thing with the BWD brand? And what's a good one to get or if I should be looking for a motorcraft? Thanks

Sorry to hear that the new switch didn't solve the problem, especially since the supposedly "correct" part should have done more than just click. I've used BW stuff for years without any problems, but as more of this stuff comes out of China, the less meaningful that history becomes.

If you're certain that your resistor wire shows continuity, the next thing I would suggest would be to test your original switch for continuity in the "run" mode (as opposed to "start" mode). If you're getting continuity in the "run" mode, then at least you know to look beyond your switch for the problem.

Good luck!
Karl