I was checking everything out to get it inspected/registered and my left rear brake light doesn't work, the turn signal and park light does work on that side. I tried switching bulbs, new bulbs don't work, there's 12 volts (checked with multimeter) at the socket when the brakes are on, but bulb doesn't light. Any ideas??

 

The main culprit that fails and having no brake lights is the steering column turn signal switch. That was the ever first mopar item I ever changed in my first mopar. I had no brake lights but everything else worked. It could be that a 'section' of that turn signal switch has failed. 'Both brake' light usually fail when that part of the switch burns out but you never know. I'd check and compare both sides of the parking/turn signal/parking circuits(wires,grounds etc) in the trunk to compare but if everthing seems good back there the next item that would make brake light fails is the turn signal switch. Its a long harness that plugs at the base of the steering columnand travels up the column where it turns into the brake light turn signal switch. When you move the turn signal lever up or down on the left of the column thats part of the turn signal switch. Youi can but them in many places. Easy to replace also.

Do you emergency Flashers work? Thats also part of the turn signal switch. Here's what it looks like.

 

Another thought is the tailight socket itself. I just had to replace the socket in my 69 Charger. Brake would not light but turn signal did. I did as you did, tried new buld, same result. But I noticed the bulb did not "seat" well in the socket. Bought another one through Tony's Mopar parts and it did the trick. Worth trying atleast as the steering column route is much more involved, but equally probable.

Good luck

 

Thanks, I will try the turn signal switch. I even tried a seperate ground and still no brake light.

 

How do you get the horn ring off the steering wheel to check the turn signal switch?

 

I'm not sure what kind of steering wheel you have. My 70 Runeer was simple. The center section of the horn had a Road Runner emblem and it just popped out with a little screwdriver and hehind that was the horn ring bolt that held the horn ring and steering wheel in place. If there aren't any visible screws/bolts and there's no center cap to pop out it must just snap into place but thats a guess. I don't have a manual for any of my mopars any more that show each year. You might post on Moparts.com I'm sure they could tell you. My first turn signal switch replacement was 30 years ago so my memory has gone abit since then. I also did my recent GTX but I think that steering wheel is designed alittle different, at least on the surface. Wish I could help. keep me updated!!!
Chris