Tail Light Problem, No Right Rear Drive light

[Jason McCandless]

Trying to trouble shoot my 64 C. The car had both rear drive lights working after I installed new tail light assemblies a few months back. However, the right rear drive light became non-functional after driving in heavy rain.

As noted, they are both new tail light assemblies, the right rear blinker/brake light works fine. I swapped the wires and was able to get the right drive light to blink. The light is good.

After studying both sides, I wonder if I am missing a ground.

On the left side of the car, the wiring loom includes three wires, the drive light wire, blinker/brake wire, and a brown ground. There is also a ground strap from the chassis. Each ground attaches on an outboard post of the tail light (vs. the single inboard post)

On the right side, the wire loom only includes the drive light and blinker/brake wire. There is a ground strap from the chassis, connected at an outboard post. There is no ground wire from the loom. I am missing the oval backing plate on this side (see picture), but that's been gone for while and the light worked without it.

I took the front park and rear tail lights off the car, cleaned the contact points/ground, and the chassis points. Fuse 7 is good.

Studying the factory wiring diagram, there looks to be a ground wire that runs from the left rear light assembly to each license light and the reverse light. Not to the right rear assembly.

I have Joe Leoni's books/diagrams (and headlight relay). It does show a ground from the right license light to the right rear assembly. I don't see one though. Not sure if that is it, because the light worked before. The rain made me think there was water getting in somewhere, but it all seemed in order...

Thoughts?

[Gert Gehlhaar]

I am sure that with your explanation that you have a ground problem. Easy test is to make a pigtail with a clip on each end and connect one end to the tail light and the other to a good known ground. If it works you have just found the problem. Good Luck.

[Guest]

Jason McCandless wrote:

Trying to trouble shoot my 64 C. The car had both rear drive lights
working after I installed new tail light assemblies a few months back.
However, the right rear drive light became non-functional after
driving in heavy rain.

As noted, they are both new tail light assemblies, the right rear
blinker/brake light works fine. I swapped the wires and was able to
get the right drive light to blink. The light is good.

After studying both sides, I wonder if I am missing a ground.

On the left side of the car, the wiring loom includes three wires, the
drive light wire, blinker/brake wire, and a brown ground. There is
also a ground strap from the chassis. Each ground attaches on an
outboard post of the tail light (vs. the single inboard post)

On the right side, the wire loom only includes the drive light and
blinker/brake wire. There is a ground strap from the chassis,
connected at an outboard post. There is no ground wire from the loom.
I am missing the oval backing plate on this side (see picture), but
that's been gone for while and the light worked without it.

I took the front park and rear tail lights off the car, cleaned the
contact points/ground, and the chassis points. Fuse 7 is good.

Studying the factory wiring diagram, there looks to be a ground wire
that runs from the left rear light assembly to each license light and
the reverse light. Not to the right rear assembly.

I have Joe Leoni's books/diagrams (and headlight relay). It does show
a ground from the right license light to the right rear assembly. I
don't see one though. Not sure if that is it, because the light worked
before. The rain made me think there was water getting in somewhere,
but it all seemed in order...

Thoughts? Pictures below...

Here is the left light:


Here is the right light:

Jason,
The ground is the metal strap from the body the brown ground wire is
supply ground to other items. If you have a test light poke it in there
to see if volts are happening don't use a volt meter its too sensitive.
You can try to supply ground with a wire from the body to the light and
see what happens.

Alan

Alan

Post generated using Mail2Forum via email.

[Jason McCandless]

Well, it wasn't a ground. I wired up a ground wire to the body, but no luck.

Alan, unfortunately, I don't have a test light, only a volt meter...and I am sure I am not using it correctly...

Back to the drawing board...

New info: The lights on the speedometer instrument are out also (58b), but I checked and the speedo bulbs are good, the 'can' is firmly grounded through the mount strap/brack. No other instruments lights are out, the dimmer function works, etc.

The speedo bulbs (58b) are wired to the headlight switch right next to fuse 7 (58 ), fuse 7 is the rear driving light connection. Could a problem be in there? All, of the bullets and connections on the back of the headlight switch look and feel solid, in place.

Any insight? Ideas?

Many thanks,
Jason

[Rick Woltz]

I had a similar problem and fixed it by, disconnecting the battery, removing the stearing wheel and taking some good electrical contact cleaner and spraying it into the turn signal assembly and moving the control lever around and respraying and moving it around until all the dirt and dust came out and it started working correctly. Be sure and surround the area with rags and a follow up blast of compressed air also helps dry out the contact assembly.

[Jason McCandless]

Rick,

Was this for your blinker or the driving/brake light?

I see that the blinker wire runs to the steering column. Or is it, that this is part of the circuit/loop?

Jason

[Norm Miller]

Jason,

Based on what you have done and observed so far I would suggest checking the continuity from the feed wire to the center pole in the light socket and also check the resistance.

I would that the rain water got into the after market light assy. and has caused some corrosion.

I'm not familiar with C fuse block but on the A the front park light and the rear driving light wires both attach to fuse 7. it is possible that you have an open circuit at that connection. Does the rt. front park light work?

Try taking an old bulb socket with a good bulb and hook the taillight wire up and ground the socket. If that works your system is OK and it's the new light unit.

Nothing in the signal switch has anything to do with the tail light.

Norm C356C
#3294

[Roy Smalley]

Did you check the fuse and power to the wire that feeds that light?