Intermittent tail light

[disnylanddad]

Having a intermittent problem with my rear driver side tail light. It will say rear lamp out on the HUD and rapid flash the turn signal on that side. When this happens my break light on that side also stops working. When it first stopped working, I replaced the bulb even though it didn't look burnt out. It then worked for several days and stopped again. I then put the old bulb back in, and it started working again. So I replaced the lamp socket. Again worked for several days and then stopped. I then traced out the wires and could not find any issues. So I replaced the plug for the socket. Again worked for a few days then stopped. I am reading 12vdc at the socket terminals with the truck not running and the lights on and 14vdc when I start the truck. And yet bulb still will not light till I unplugg it and plugg back in. Suspected it may be a ground issue so I grounded that circuit direct but still did not work even though I have power

 

[disnylanddad]

Ok this may sound stupid but It stopped working again. I pulled out my bulb and turned it around. It then started working again and has now been working for the last 2 weeks. The way the socket is designed the bulb can go in either way. Is it possible I just had it in backwards this whole time?

 

[1999 White C5 Coupe]

Ok this may sound stupid but It stopped working again. I pulled out my bulb and turned it around. It then started working again and has now been working for the last 2 weeks. The way the socket is designed the bulb can go in either way. Is it possible I just had it in backwards this whole time?

It is possible to have the bulb in the wrong way (rotated 180 degrees).

The bulb should have two filaments - brake and tail. Look closely at the bulb base - there should be two tabs, one on each side. One is higher than the other side. This normally ensures the bulb is not inserted the wrong way.