sounds like a bad ground issue to me. you have a ground point back there, find it and clean it

 

Worth another shot shot. I cleaned the entire tail lamp assembly when I tool it out to install the new bulb.

 

jaystekan, do you have an aftermarket Trailer Wiring Harness installed? they can short out and cause weird taillight/headlight issues... had a problem with mine and it was fine after i took the wiring harness right out. try it.

 

Unfortunately I don't. I am hoping to avoid having to purchase a whole new taillight assembly.

 

you will most likely need to remove the whole rear panel in the back (the one the access panel is in) and you should find what looks like a plug with a bunch of wires in it (they should all be the same color) and it is just bolted down, it wont be connected to anything. then unbolt it and clean the metal where it bolts really well (I use a wire brush) then rebolt it.

 

did this work? i have an 03 disco which has the same problem with the driver's side tailight. everything works fine when headlights are off, but once i turn my headlights on and then push the brakes, my whole driver's side rear tailight goes out...

 

I had the same problem... I found the metal contact points in socket had lost some of their spring to make good contact. I took a small screw driver and bent the two in the bottom up some. There is also a small one on the side that I pulled out a bit. Plugged the bulbs in and everything works great.

 

this is exactly what I was going to suggest; I had this happen to me and bent the tabs back to create a better contact and no problems since. good luck!

 

did this work, I have the same problem

 

Rover Chris, where is this whole rear panel in the back?