Faint rear brake lights / turn signals

[RPM-Racing]

Hello,
I have used this board for the past 16 months to help figure out problems, more over find the best solutions. But I have not seen this one and about to pull my hair out.

When I start the truck the rear turn signals and the brake lights work great, after driving for a few minutes the rear lights work but so faint the bulb only glows orange on the filament, and the front turn signals work as bright and great still. I have replaced all the wiring from rear light sockets to the firewall. I have pulled the light sockets apart and cleaned them to no end(both the brass and and the metal socket and still the same problem. I have followed all the wiring in the dash to check for any isues. The wierdest thing is I added back up lights to the truck as they did not have them. I have used stock replacements from LMC truck and ran a seperate wire to the dash with a metal toggle switch with an LED end. When I have the switch hooked to the lights and NOT to any power source the LED goes on when I put a turn signal on or press on the brakes when they are in the faint mode. As soon as I get out the truck and ground myself most of the time the lights work good again.

I saw on the 67 to 72 page the guys there had to solder the brass part to the metal socket. I was thinking about that but why to do they work then not.
I am going crazy!!!!! 16 months of resto, on the verg of being done and I can not drive it more than 5 minutes without this happening.

[Breadstick]

Not sure if this is your problem, but all the lights in the back of truck are connected to the turn signal switch in the steering column. If you've already replaced all the wiring (especially grounds), I would check into that. If it's original, they're known to cause all kinds of weird problems.

[RPM-Racing]

I ordered one from LMC truck with the rest of the wiring and it is not the right one, so I took all the copper contacts out, cleaned them all back to the shining copper finish and put it all back together and tested them all everything seems to work fine. I do have another one on the way from LMC. I am just confused on the stops after a few minutes then as soon as I get out of the truck it all works.

Thank you,

[kieth]

when I was rebuilding my 66 I used all original light housings but I made one simple change. We soldered a ground wire to each light housing, then tied the grounds together with a grounding block. All lights now work like a champ.....bright...........give thaqt a try you will be amazed.......no more looking for bad grounds. Kieth

[RPM-Racing]

Thank you, Do you ever have one of those moments when everthing become clear and you realize that you need to slow down. When testing the lights that are mounted to the box, do not use the frame as the ground for the test light as you instantly fix the problem until you diconnect the test light.

The box is wood decked, then there is a rubber mount, then all the it I took all that time to seal the frame / paint the frame to make it look great. With all this when the truck was still the lights worked, when the truck is moving and shaking the box would not ground and that the LED light on the dash for my reverse lights was trying to act as the ground.

Keith, your advise helped, I put a ground strap from the box to the frame and problems fixed. Tonight I am going to solder ground wires to the light sockets as well and ground them to the frame for added security.

Thank you again.

[LostMy65]

Poor ground connection was my problem for faint rear lights. Cleaned the connection and all is bright now.
Posted via Mobile Device

[Indian113]

I ran a #10 ground wire from battery to a junction block at the rear of my truck and ran seperate grounds to tailights and turnsignals. It really made a difference in my lights.

[low79fx]

I did the same to me tail lights. I soldered a separate wire to the lamp socket and attached to frame when routing new wires. The problem with the original design is that ground is depending on the very minimal surface contact that the screw that holds your rear taillight housing provides. Which amounts to only the thickness of the sheet metal touching the thread, getting a little air, dirt or moisture in there and you will sure lose your ground source or create a lot of resistance for ground to complete. Thus causing your dim light problem. Yes try soldering a wire to lamp socket for a good ground as others have recommended.