2nd Gen Non-Engine/Transmission Ignition switch came on by itself...yes it really did

[tjblacken]

I really hesitated to post this since even my wife called bull when I came in and told her...and I have some self respect as a decent mechanic.

So I was cleaning the interior of my 98.5 Ram Diesel (80,000 mi truck) and was in the back seat cleaning the rear window. My truck keys were in my pocket. Truck had not been started in two days.
What first caught my attention was my radar detector going off. I turned and saw the radio, all the dash gauges, my aftermarket gauges and the vent fan were now all on and running. Exactly as if the key were inserted and turned to "on". I took my key from my pocket and put it in the ignition. Could not get the equipment to shut off using the ignition switch. I cycled the key about 6 time with no effect. I then started the truck, ran it for about a minute and everything was back to normal. WHAT HAPPENED? Been around wrenches and vehicles for 50 years, never would believe this if I hadn't seen it myself. (no it doesnt have a remote start system, or even a key fob).

Guess I could put my sleeping bag in the truck and wait for a re occurrence, or save a little time and ask here!
I'm going to replace the ignition switch anyway, but has anyone every seen this failure before?

No Christine jokes please!!

 

[SnoKing]

You got it all cleaned up and it was hot to trot! SNOKING

 

[GrantP]

Bad ignition switch? Just a guess...

 

[MLee]

You just rubbed it the right way!!

 

[EDankievitch]

I had an instance with the 2002 I had years ago where it would not shut down. Key in off position and removed and everything kep running as if the key was in. Only way I was able to get it to turn off was to try to start it again after the 3rd try everything went back to normal. Never did it again. Strange...

 

[Road Dog]

I have an Edge Juice with a turbo cool down setting that keeps the engine and all sorts of circuits powered until the exhaust temperature is under 350F.

Basically the RUN circuit in your truck was getting +12V. There's dozens of points in the wiring harness where a fault can provide the +12V. As an example, the radio is powered by BATTERY (always on) and uses the RUN as a signal to turn on. A fault (software or hardware) can connect the BATTERY and RUN circuits within the radio. Another place where both circuits exist is the central control module (which controls everything from the heated seats to the keyless entry).

There are many micro-computers in the truck and once they reset the problem fixes itself and that's that.