Can someone tell me what the “resistor” is for at the parking brake switch. And is it a resistor?

 

It's possible that it is a diode to limit the amount of current spike when the parking brake is engaged. If you could post a picture of it I might be able to tell from that. Or look it up in the schematic in the factory service manual.

 

Here are some pictures:

 

Looks like a diode with a 0.5 amp capacity.