cummins isb engine will not shut down

Took steering column apart, found no suspect wiring. Started up and turned ignition key off. Still running. I then removed the wiring plug from back of ignition switch to rule out switch. Still running. I then checked for voltage at the wires on the ignition plug expecting to find voltage only at battery terminal. Instead I found voltage at battery, ignition, and G1 terminals.
Does this sound normal, or am I getting crossover from other wiring?
Thanks for the interest in my predicament!

I have your exact coach; had electrical issues that ultimately turned out to be pinched wires in the steering column. In my case, it caused all gauges to go dead (and blow a fuse). It was hard to duplicate (like your issue), but I was finally able to prove it occurred only with the steering wheel tiled at a certain angle. Never found a specific short, but a couple business cards between the wires at the tightest bend I could see solved the problem (has been ok for several years now).

No promises, but I’d take plastic shroud off the steering column, tilt it every direction possible and look for tight wires.

Also – get the wiring diagram (Winnebago web page) to narrow down which wires are possible “carriers” of your signal that won’t turn off when the key is off.

Moved from Forum Technical Support

Thanks for things to look for. Sometimes when I type in Cummins engine, even mentioning motor home, I get replies from people who think I have a Dodge truck. Really fun trying to separate the information! Thanks again!

admiraljim wrote:
Do not believe I have a fuel shut-off solenoid. I think the ECM controls the injector pump. Ignition switch was checked and is OK. Thanks for the replies!

IF ignition switch was checked OK how is DC voltage getting thru ignition to ECM with switch OFF?

DO you have a tilt steering wheel?....pinched wire

Do you have any 'mods'....programmer or turbo delay ?


Have you tried holding your foot on brake pedal and then turning ignition key off?

Have you checked for 'codes'?

Negative on the runaway. Engine runs smooth before turning off key switch, then having to pull main harness plug to shut down. Many thanks for your input!

was there smoke? possible to "runaway" by burning crankcase oil leaking past fuel pump, turbo seals, gaskets, etc. no electrical necessary. see youtube "diesel runaway"

nasty stuff.

Do not believe I have a fuel shut-off solenoid. I think the ECM controls the injector pump. Ignition switch was checked and is OK. Thanks for the replies!

Bad ignition switch

Bad fuel shut off solenoid.