Have a intermittent driver side rear brake light issue. Basically works when it wants to. Replaced the original rear harness cleaned the ground. New turn signal switch about 2 years ago.
Had it out today, initially both brakes lights working, reverse to park ok, reverse to park to drive ok, reverse to drive ok, then reverse again then it stops working. I can go for a short drive and it starts working again. My wife pointed out it started working again after I used my turn signal. All other lights work fine.
Any ideas appreciated. Cheers!

 

What kind of shape are the bulb sockets in? Might be time for new ones.

 

rear harness is brand new including sockets.

 

Might be that turn signal switch.

 

There is not short cut here. You are going to have to wait until its not working and track down the issue. Step one, are you losing power or ground? Even a bulb can be intermittent.

 

I agree no short cut. I haven't had the chance yet to see if it's power or ground. But I did run a ground wire from each of the left tail light sockets to ground and this didn't help. So I can't 100% say it's not the ground until I check it with a meter. But it is looking like a power issue. Forgot to mention I did swap the bulbs with the right side tail lights, same issue on the left side.