Taillight problem

[henry's 31]

Today I installed a new wiring harness on my 31 Roadster pickup that I purchased without any lights connected. My headlights are working, horn and breaklights also work perfectly. But I can't get my taillights to come on when I turn my parking or headlights and it appears only one of the many LED bulbs come on when I turn the lights on. My guess is a ground problem but how can I correct this. Any suggestions out there?


I thank you in advance for any suggestions.

[Synchro909]

Have you tested the light say, by connecting it directly to a battery? It sounds to me like it could be Kaput.

[jrelliott]

Have you tested voltage at the bulbs that are not coming on? That would be the first place to start. If you have voltage measure the resistance from the bulb socket to ground. Turn off the lights before you make this last test can ruin the meter. I ran separate ground wires from the tail light housing and head light housings to chassis ground inside the harnesses so would not be seen. The ground connection had a soldered on terminal lug with a star washer between the lug and the chassis to insure a good connection. On the headlights had to remove the original connections at the conduits to headlight and using slip connectors on the head light wires. This prevented any shorting and flickering headlights.

[henry's 31]

Hi Jrelliott:


Thanks for your reply. I am not able to work on it today, but will try it tomorrow morning. I was planning on removing the nuts that hold the tailight assembly and making sure the metal is clean and not painted and then run a wire to the frame. I would think I have to do it to each tailight. The previous owner that attempted to restore the pickup placed the headlights on the rear fenders and not below the bed. If I repaint it in the future I will place them where they go. At this time the paint is too nice to do it otherwise. Thanks for your reply!


Al

[henry's 31]

Hi Synchro909:


Thanks for your reply. The tailights are new out of the package,


Thanks for your reply,


Al

[ronn]

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Thanks for your reply. The tailights are new out of the package,


all the more reason to test them separately............

[henry's 31]

Hi Ronn:
Thanks for the suggestion, got it.


Al

[jak]

With LED's YOU MUST run a DIRECT ground Wire from each of the light buckets. The original method of grounding does not always work with the LED's.

[henry's 31]

Hi Jak:
Thanks for your reply. Could you describe how you did it.


Thanks again,


Al

[31Cabriolet68-C]

You might try this,
Check all the black rubber connectors between the main wiring loom and the wires that feed out to the lamp sockets. The new ones may need to have the metal connector inside the black cover opened up a bit to accept the tip on the wire, then get crimped tight... might give any/all of those connectors a nice squeeze with the vice grips.
Helped me... BTW: thanks sent out to Patrick Musante for the suggestion.

[Dick M]

I mounted a wire in between the mounting bracket and mounting screw. I then ran the wire through the bracket and grounded it to the frame. I have done this with both headlights and tail lights with good success.

[henry's 31]

Hi Cabriolet:


I was thinking that could be the problem. Will Try to do that


Thanks for the reply,


Al

[henry's 31]

Hi Dick M:


Thank you for describing how to properly run the ground wire.


I will try all of the above and see if I can get them to work.


Thanks for the reply,


Al

[jak]

I ran a wire from the screw that attaches the tail light bucket to the stand, down to a good ground. I tested for a good ground using a meter between the bucket and different places on the frame. I tried to hide the ground wire as best i could but if you look closely you can see it.

Originally Posted by henry's 31

Hi Jak:
Thanks for your reply. Could you describe how you did it.


Thanks again,


Al

[jrelliott]

Going back to the original post, headlights and brake lights work. Is this the Stop light bulb, or the upper bulb? If this bulb is working, you must have a good ground connection between the frame, fender, tail light bracket and bulb socket. Do you have voltage to the lower bulb socket which is the brake (Tail) light which is a lower candle power bulb than the upper bulb. When you have either the parking lights or the headlights on is there voltage to the center contact on this bulb socket. This wire is the black wire coming out of the light switch to the brake (Tail) lights. The Stop light wire is the green wire going to the stop light switch, then to the stop lights.

[JayJay]

FWIW, I had an issue with the LED inserts for the taillights - one side worked and the other side failed within five minutes of installation. Tested them on a battery and it was definitely the unit. Snyders was great about shipping me a replacement immediately and giving me a return shipment label. But as the LED units are at their core electronic devices, infant mortality is a real issue. Best way to isolate where the problem is is to start with a direct hookup between the wires and a battery, then gradually add in elements until you find the failure point.

[henry's 31]

Hi:


I am currently traveling but I will check all of the above as soon as I get back. I guess I will not be surprised if the units are at fault.


Thank you for all that responded. I surely appreciate it. I will try any suggestion given.