Anybody Ever Seen Something Like This:

[Rob]

This switch applies power to a wire that runs to the rear of the truck, (not hooked to anything) and only has voltage when the engine stop cable is pushed in. It does not power the wire when the engine stop cable is pulled out and engine is not running. I've never seen anything hooked up to operate like this. I thought it looked like an "add on" to the original truck as the bracket does not look like a factory part to me. There is a contactor passing current from the main battery cable on the engine starter through this switch that is enabled via a toggle switch installed into the dash. This contactor will handle a much larger current load than this switch but the switch carries full circuit load.

Any ideas what this might have been used for?

Thanks,

Rob

[Greg Rider]

Sounds like maybe a fuel pump shut-off? Power is off when engine stop is pullled> shut off fuel. Power on/off with ignition switch> fuel control. May have been a booster pump to make up for a weak lift pump.

[ThaddeusW]

Running to the rear of the truck? Hooked to anything? Any other wires running back up front?

If there was another wire running back to the front and the switch worked the opposite then it would be for a starter bumping switch. Some guys have a button on the rear of the truck that bumps the starter when the truck is shut off so they can easily hook up trailer draw bars. Just leave the truck in reverse and go around back, lift the draw bar and then bump the starter to bring the truck back to get the eye into the coupler. Often found on transfer dump trucks.

[Lmackattack]

I could see it used as a bump starter thing but god thats a big risk to do with a mechnical engine with the engine stop cable in the run position. the truck could just take off or crush you.

what about a trailer battery that was powered off this wire?

[theakerstwo]

I think Tad has got it because when stop ant pulled no power to the switch so it sounds safe to me.

[ThaddeusW]

I think Tad has got it because when stop ant pulled no power to the switch so it sounds safe to me.

LOL I think we are all confused. Reading what Rob wrote again tells it like this:

Stop pushed in which lets engine run: Power to the wire.

Stop pulled out which kills the engine: No power to the wire.

In addition the switch is fed via a relay that is switched on or off by an in cab switch.

So its opposite of what a starter bumping switch should have. Trent might be right, it could be there to power a trailer accessory.