rear tail/Brake light not illuminating

[fgross2006]

I have had this issue on and off for as long as I've owned this car since 2012.

I have had people pull up to me and say one tail/brake light is out. But when I check, they seem OK.

I just got pulled over today and luckily the cop let me go telling me to fix the problem or next time he will write tickets.

I came home and checked the voltage to the driver side tail light and found only 6 volts instead of 12.

Changing the bulb connectors seems a logical thing but what else would be causing me to lose voltage on only one tail light?

[4-barrel Mike]

Check your grounds.

Mike

[fgross2006]

Check your grounds.

Mike

I had the car at my mechanic last summer and we went through all the rear light wires and grounds together and found everything to be clean and functioning. The lights looked OK at the time too. And today again, when I went to check them both lit up just fine and I found 11 volts at all three brake lights. Yet earlier this afternoon, the driver side brake light was barely visible when I backed up to a glass window and hit the brakes.

[4-barrel Mike]

Ok. Are the turn signals nice and bright?

Mike

[gr79]

Had the same issue a month ago. Actually 2 at once.
Slowly got worse.
Graphic display red led lit running taillight out. Then brake light led. And every combo in between.
Intermittent wacko. No pattern. Dim, bright, or nothing, one or both ds tailights/brake.
Slow turn signals both sides. Hazards fine. Pass side fine. Ft ts, marker lights, fine.

Glass window test passed sometimes, sometimes not.
Bulb swaps, old and new= no change.
Wire wiggle sometimes corrected problem for an inconsistent time span.
Did not check voltage. Either be 12v on, zero volts off.
Using lighted test probe as a jumper, verified bad connections internally at socket.

Replaced ds outer tail light socket. That corrected running/brake light problem, except slow ts.
Replaced ts flasher. That corrected ts problem.
Everything works like new again.

[Haystack]

I find its usually the connectors on the brade switch under the pedal shorting out. I chop it off and throw space connectors on and forget about it.

Just an fyi, almost every car ive had measures around 11 volts at the tail light even when the car is 13+ at idle. My tbird has six lights per side, plus two markers and the of course the 3rd brake light.

That makes something like 15 amps per tail light, all ran through a tiny wire. 2 amps per 1157 fully lit, and 1 amp when only one filament is lit. The 1156 usually draws around 1 or 1.5 amps.

So almost 30amps is ran intermittently through roughly 20 feet of undersized wire.

[fgross2006]

Ok. Are the turn signals nice and bright?

Mike

All lights on my car, internal and external have been replaced with LED's except for the headlights. Turn signals work fine and are very bright.

I went with superbrightleds and got the brightest lights they offered for each bulb location.