I have a 2000 MC Sierra Extended Cab 3-Door. I removed the trim behind the driver's seat to do some rust repair and found that there is a relay clipped to the pillar behind the driver's door. It is a single pole single throw relay with orange, white, black and brown wires. Does anyone know what it is controlling? (So that when whatever it is dies, I'll find the relay, as will everyone who reads your response.) What a goofy place for a relay! To access it, I would have to remove the trim panel, which involves removing shoulder belts and more. I tried to trace the wires, but they enter a bundle and go to a tee, with several others.
Thanks!

 

The relay is energized by the Aux Lamp switch on the dash. (The Aux Lamps are part of the snow plowing package. I believe wires for the lights are above the headliner for aftermarket installation, but I don't know for certain. I don't have any auxiliary lamps.) I posted my findings here with the hope that if someone has trouble with their auxiliary lamps they will know where the relay is hidden.