truck wont stay running
 

Hello everyone, I have bought a 1987 dodge w250. It will only run while the starter is engaged. Once the key goes back into the run position it dies. I have replaced the balast resistor, voltage regulator, and the starter switch. It is a non tilt wheel. Any help would be appreciated. Also i stole this pic from someone here on the forum. I found this forum because of this pic. That white switch with the blue and blue and black wire, what is that my key lock is always holding it down. I took it out to see if that would work but it doesn't spring up. I wanted to replace it with a new key lock but I don't know what it is or does.https://www.dieseltruckresource.com/...needs-edit.jpg

That is mostly like the buzzer for the key left in the ignition. Sounds like a problem with the starter relay, or with the ignition switch....which might be down farther on the top of the steering column, might be a metal rod or two that run down to it? When you turn on the ignition and turn the key to start it sends power to the ignition and starter system to start up, but once you let off the key that power source is still supposed to be active to the ignition keep the system working.

Assuming a gas engine, this fault is the run circuit, ignition switch, ballast resistor, or associated wiring and connectors.

yes sir it is a gas engine. I have replaced the ignition switch and balast resistor. The next thing I was going to do was check the wiring harness from connector to truck.

Here's the layout. The ignition switch supplies 12v to the coil through a ballast resistor. The second small terminal on the starter solenoid supplies 12V to the coil when the starter is turning bypassing both the ignition switch and the ballast resistor. You'll have to get a diagram for the vehicle to know exactly how it's routed through the wiring, but it should be easy to trace.