Rear Exterior Lighting Problem

[Rinkydink]

Headlights and turn indicators work perfectly up front. Rear is a different story. Tail lights and blinkers are dim. I have no brake lights. Guessing the "dim" is due to something being crossed up or shorted, but why wouldn't that affect the front?

I've tried following the wiring harness that runs under chasis to the rear of the rig. Thought I found a few bad connections, but cleaned those up and no improvement. There are a few areas of the harness that become very difficult to follow. Before I start tearing things apart looking for a bad connection, any input or obvious issues I should be looking for?

1980 D23 Brave on a Dodge

Wiring harness has 4 wires. Black, Brown, Green & Yellow. There is a white wire on the fixtures that is ground to the chasis.

Thanks guys

[Froggy1936]

Most common reason for functioning but dim lights is a bad ground   With any old wireing problems  sometimes its easier to run new wires from source to light rather than try to find short or broken wire. Grounds that were originally thru mounting can be repaired with a ground wire to a known good ground (the body is not reliable go to the frame or all the way to the ground terminal of the battery) The object is to make the light work not retain originality  Frank

[DaveVA78Chieftain]

Like Frank said, you have a bad path to ground for the rear lights.

The signals are having to find a path to ground by going through other bulbs (several bulbs in series).   This results in a large voltage drop at several points.  The front bulbs are not having to do that so they do not exhibit the problem.  Sort of like a christmas tree light set.  Because they are in series, if you short out one bulb the others get brighter.

Dave

[tiinytina]

Like above bad ground.... you can also try to find the ground (usually a white wire screwed into "somewhere"), sand off the wire end, and replace the screw, sand off where it is screwed into as well.  Also scrape with a pen knife where the bulb base  hits the base of each socket to make sure that connection point is clean as well.

Tina

[ClassCKing]

had about the same problem found out that the ground wire for the  light had some corrosion on it and the bulb.. replaced the bulb and cleaned the corrosion..and wallah lights..had a small crack in the lens replaced that to..no problem since