Here we go again. Only now I'm thinking loose ground wire. I say this because this happened twice, today, while driving in the freeway. Drivers side rear only. Hyper blinking, then normal, then hyper. Now comes the question, where is this system grounded? Can I make another ground?
I will resolve this issue.

 

Ground under the stop light.

Ground locations

 

Thanx donbrew. Will check it out

 

Did some continuity checks, disconnected ground wire from body, scotchbrited ground connector and body stud, reassembled and light works.
Let's see what tomorrow brings.
Thanx again for the help and encouragement.

OldBlue, I have to find reasons not to drive 'Toughie', I enjoy it to much

 

No lights again. Could this issue be caused by the multi-purpose switch?
If I had hair I would be pulling in it by now.

 

Only thing I can think of is a broken wire somewhere near where you wiggled it. The brake/turn light is on the same wire from the BCM to the light.

 

I think what bothers me the most is this is just the fact that it works, then it doesn't, then it works, then it doesn't. I understand that the L and R tail/brake lights are on different circuits so I'm only dealing with the drivers side rear.
I agree that this sounds like a broken wire, but where? My last resistant check from the bulb socket to just behind the rear door checked good. I will admit that I'm perplexed but I'm not beaten.
Next, I want to reattach the resistor to a different ground location.

 

If this is a single tail light not working, a broken wire would have to be close to the socket. By the wiring diagram, all the tail light brown wires connect together close to the rear sockets. For just one to go out the break would have to be between that junction and the socket.
Check that area but I'll also suggest rechecking the ground, socket and even the bulb.

 

I think we are talking the brake/turn light.

 

I would try putting a OEM incandescent bulb in it. Also checking resistance only tells you if a wire is broken in two, it does not detect a 24 stranded wire with 23 strands broken and only one strand attached, it still rings good, but this wire will not pass current as well and light will be dim.