Door lock switch
 

Hey guys, I have a 2002 GMC 1500. Still fighting abs issues. But another problem I'm having with the truck is the door locks. The truck doors lock when in drive when the truck gets up to speed so I think the fuse is okay But neither of the door lock switches work. The drivers side window was stuck in the down position for a while before I got the truck. Could have been some water damage in the switch. ??? The window is repaired and working well. Is there a relay I should be looking for or any other helpful hints I can start hunting down. Does one switch work through the drivers door like a master? I'm wondering if the switch is hooped and needs replaced. Any idea how I'd be able to tell. I haven't picked up a manual for the truck yet so not sure where to start looking. Any hints would be awesome and appreciated.
Thanks Vince