At the very bottom of the instrument panel is a red button, its next to the steering column and is wired all the way down to the upper part of the transmission and rear drive shaft. There are two wires that look like they connect to it but I have no idea what its for?

 

Sounds like it might go to an overdrive or gear splitter, hard to say. Nothing happens when you push it?

 

doesn't sound factory. pics to what it is wired to might help.

 

Oh that is the rocket boost button... Or maybe the ejection button...

 

Flux capacitor on/off button?

 

I was thinking Men In Black lol... "dont ever, push the little red button"

 

All this time I thought it was the manual oiler for the muffler bearings.

 

Shouldn't be. The dentsides came with automatic oilers whereas the bumpsides were still manual.

 

I'll put a pic up ASAP.

 

Which is exactly why so many bump owners seek out the auto oilers from dents just like disc brakes.

Never, never push the red button unless it is your absolute last resort. It activates the Bat Phone.

 

Jeez, don't push the RED BUTTON!! It will turn your truck into an 85' Silverado!!!! All joking aside, I don't think our trucks came with a push button under the dash. Can you trace the wires coming from it?

 

Don't forget that it requires 710 oil poured in through a left-handed funnel...

But Seriously:
from the description the OP gave I would guess the PO was trying to make the reverse lights work....

 

Transbrake??
Oil slick??
Smoke screen??
Self destruct??

 

Dont forget ejector seat

 

The red button had two wires, one going to the horn and the other going to the solenoid.