Tahoe parking lights and tail lights remain on. I have pulled and replaced the parking light relay to no avail. I have removed the switch and lights remain on with switch unplugged. I have checked the trailer plug and nothing loose there. Please anyone have any idea how to fix this?

 

Are the lights still on when the relay is removed?
Then, something in the wiring is powering the circuit. See if removing the 'TRLR PRK' fuse fixes the problem. If it does then revisit the trailer plug especially the backside looking for corrosion or pinched wires.

Do you hear the relay clicking when you plug it in?
The BCM turns the relay on when it sees the light switch closed. I'd try doing a BCM reset (disconnect the battery).

 

shipper1, did you find a solution to this??? I'm having the same issue. When the mechanic pulled the relay, the lights were still on!