Flux Capictor?

Tyr getting under the dash and see where the wires go.

Does the truck have any extra lights or accessories?

Definitley not a Ford OEM switch.

 

No exterior aftermarket lights, while running doesn't seem to do anything as far as the engine is concerned, additionally can't tell where the wires go without tearing about the entire dash. Is it possible that it is an aftermarket switch for an engine block heater or simlar ?

 

A few questions: is your truck really set to to tow? Is it a single pole, single throw switch, or a double pole, double throw switch. A double pole, double throw switch, has three positions; top, middle, and bottom. If you turn the switch to on, and you are driving, when you come up to a stop light, sign, whatever, does it buck and jump and try to die?

If its any of the last two items, its a torque converter lockup switch. It keeps the torque converter in the tranny locked longer than the PCM normally does. This is a good thing, unless you are down to about 15 mph, or lower. Then, you need to unlock it, so you can stop and go normally.

Considering its right there on the lower dash, kinda makes me believe this may be the case. Easy to get to, easy to control. When the light is on, converter is locked.

 

Thanks for the feed back. It looks like nothing changes at all if you flip it on if you are driving or stoped with the truck on or off. Never had a diesel this will be my first one. Also it is not set for towing. This is the truck listed Berkenkotter Motors | 2003 Ford F-250 Super Duty Lariat

 

Whenever you flip that switch some guys truck somewhere else keeps starting and stopping and he can't figure out why...

 

Removing the lower panel under the steering wheel, "tearing" into the dash panel, it does not make.

Take a quarter, turn the two big flathead plastic screws 1/2 (IIRC) of a turn, then pull the cover off and look.

It's so easy even you can do it.

I don't mean to sound mean, but my crystal ball is in the shop, getting a tune-up. Without it, it's a little hard to trace wires over the internet if you're not willing to at least pull the cover and look, or take a picture or something.

 

Another possibility is an auxiliary GPR switch to keep the glow plugs on longer than normal (although I don't know why anyone would want to do that). Does the light by the switch come on only with the key on, or at any time? Just another clue to go by.

It could be something someone has removed, but left the switch and light in place. :shrug03:

 

:lol:

 

is it an "IDLE UP" switch? put on the parking brake and turn it on.....

 

is it an "IDLE UP" switch? put on the parking brake and turn it on.....

That makes the most sense to me. :thumbsup:

It'd have some wires and resistors between it and the accelerator pedal wiring.

 

Or maybe a 2wd low switch (turns off the autolock front hubs). That's the only extra switch in my truck. If so would be spliced into a wire going into the vacuum switch right behind the passenger side battery.