I've rewired my truck with a Painless harness and once I turned it over the ignition wouldn't turn it off. I pulled the voltage regulator wire to kill it. Reconnected the voltage reg. wire and tried it again with same result. After killing the engine I checked the coil for voltage with the ignition Off- 0volts and with it On but not cranking- 0volts. I checked that the correct wires from the solenoid were connected to the coil, they were. I've already checked the wires to the actual ignition with the diagram and they're all correct.

Below is what I just found on the Painless website, their Tech's are only available Mon-Fri so I can't call and ask.

Engine Run On.
An engine that still runs after turning the ignition key off is a victim of engine run on. Engine run on can be caused by several things.

Faulty alternator/regulator. GM 10SI and 12SI alternators sometimes feedback voltage into the exciter wire even when the engine is shut off. This causes voltage to feed into the ignition circuit which keeps the coil hot with voltage and causes the engine to keep running. Remedy this issue by installing a diode #276-1661 from Radio Shack, inline with the alternator exciter wire. Make sure to install the diode with the line closest to the alternator. By installing this diode you have introduced a one way gate in which voltage can only flow to the alternator and not vice-a-versa on the exciter wire.
Electric fan wired into the ignition circuit without a relay. Electric fans must be wired with a relay if they are spliced into any of the ignition hot circuits of any chassis harness. If a relay is not used the fan will feedback voltage into the ignition circuit of the harness when the ignition key is turned off while the engine is running with the fan spinning.
A faulty ignition switch. Ignition switches do wear out and break apart internally. If any of the brass parts inside the switch break apart and wedge themselves across terminals within the ignition switch, they can cause the engine to not be able to shut off.
Metal parts/fragments fall into the back side of the fuseblock. Most of Painless' harnesses have fuseblocks with open backs to them. Depending on how they are mounted within the vehicle this open area is succeptable to metal fragments, nails, staples and scrap pieces of wire to fall into it. This can cause a short accross the ignition and battery circuts of the fuseblock which in turn may cause engine run on.

I'm leaning towards the diode. If it's what I think it is then I believe there was one some where in the engine compartment before I ripped everything out and now I can't find it. Like a dummy I didn't pay attention and didn't take enough pictures while breaking down the engine. Is it the small cylinder with a wire sticking out the top?

Also the truck has no electrical fans, the ignition switch is brand new from Painless and I don't see any metal fragments in the fuse block.

Any ideas? Thank you for your thoughts.

 

Something isnt killing the power to the coil.

 

The diode may be the problem if you using the GM 10SI and 12SI alternator.