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I have a firetruck that runs great but it doesn't cut off properly after I worked on it this morning.

I now have a problem as the firetruck doesn't shut off when you turn the key off(Note: It used to..:-). This just started today as I installed(tried) to install the two speed rear axle speedometer adapter behind the dash.

So I guess my question is: what could I have done to stop the switch from working and cutting off the truck like it used too? The wires on the ignition switch look fine...but?

Any thoughts from the electrical experts?

Virginiafiretruck,

I looked at some of your pictures and noticed your truck has a alternator...is this true!

In order for the rig to keep running, the coil must be supplied with power even after mechanically turning off the key switch.

If your dinking under the dash was the really the cause of this, then maybe two adjacent wires or wire ends got mashed together so they touch. This would have to be the BATT wire on the switch and the IGN wire...take a look for wires that touch, but shouldn't.

The alternator thought was that maybe you had DA #1 tied to the coil, and possibly there was a diode in the pigtail that failed (closed ?) and now the alternator is back feeding the coil.

Something is powering the coil AFTER the ignition switch. I don't think the switch itself could fail internally and not open the circuit to the coil, but I have been known to be OTL before.

If this was truly a cause and effect deal with the install of the speedo adapter, then it is probably a mechanical wire mash situation or a missing flat washer laying across two terminals of the key switch.

Stuart

Thanks. Yes it has an alternator. I had to pull one of the wires going to the coil to shut off the motor this morning when the key didn't do the job. So you seem to be onto something with you touching wires feeding the coil. I didn't touch anything other than pushing my hands up into the tight space under that dash to mount the two speed adapter which didn't work either when I was done! I'll look at the wires again in the morning to see if I screwed that up as you post makes sense. Thanks :-)

Atomarc: You were correct! I found a wire touching and I moved it and can now shut off the truck with the key. Thanks.

Bill