Right rear body corner. This ground is normally on the inside, not the outside. Look behind carpet or if equipped through the storage/access panel.

I agree with LesMeyer on the bulbs. Not only the bulbs but corroded chassis of the lamps can cause such issues too. I'd start there, by removing the lamps. Looking behind the right one you may see the ground point attachment.

 

Okay guys. Cleaned the grounds and got all blinkers working. Changed bulbs as well. As soon as I turn the auto switch on the dash to engage night lights all power is lost to driver side rear tail light. As soon as I turn it off the power kicks back in. Very odd one indeed. Possibly switch out the switch and the multi function switch? Thoughts?

 

Check the wiring from starting point through fuse box to the rear wherever possible for repairs. We have seen so many of these electrical problems being caused by inadequate or plain messed up repairs.

This to make sure we are talking an OEM wiring. Also check the respective relais, in order to be sure they are the correct relais and properly switching.

 

Note - if looking for the ground point, its NOT THE ONE ONTOP OF THE SPARE TIRE CARRIER - That goes to the fuel pump, my truck being stuck at the end of my driveway right now being proof

 

Where did you find the ground for the Rear lamps? its not behind the housing on my 99 4dr and i cant see one on the right side of the cab outside the truck.

edit - ...its the Multi function switch, 100 dollars and a tool rental later and all should be well.