The Stovebolt Site Forums The Shop Area The Electrical Bay 1946 Chevrolet truck tail lights

So today, I find that I have NO burning tail lights when either the headlights or parking lights are on. I have rear brake lights! Where do I start troubleshooting?

Check the bulbs with an ohmmeter.

Bulbs (both stop and regular tail light) check out okay. Had already swapped out bulbs.

However, now I have no rear lights, tail lights or brake lights.

Hey Darling: Check your grounds. For the sake of trouble-shooting what I'll often do is grab my jumper cables and start by clamping the neg jumper cable to the neg battery post and bring the other end to the point where I'm trouble-shooting, using that as my connection point for a temporary ground, until I can isolate the rest of the circuit. It's amazing how age and rust between all those frame and cross member joints and body joints affects continuity eventually. Just like with a boat trailer that's been in and out of the lake a thousand times. Sometimes its easier to just run a dedicated ground back there to the tail-lights and then the other end back to the negative post. Good luck.
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Darling, 1st post you said you have brake lights, then the last post, no brake lights. Which is it?

If no tail lights but you DO have brake lights, probably a broken wire. If neither, then as Flatblu said, probably a bad ground.

Truck sitting in the garage (winter). Both tail lights and brake lights have been working. Truck has not moved since lights were last checked last week.

This morning, I was turning things on and off as part of checking them weekly during winter storage. I had no tail lights, but had brake lights. One hour later, when I revisited it, both tail lights and brake lights were not working. Truck has not be started, moved, etc between the two morning tests.

I have checked both bulbs (regular and brake) in both tailights and both are good. Just to make sure, I have even replaced them to no benefit.

I have tested voltage to the light socket buttons for both bulbs and there is no reading.

I have run a number wire from the negative battery post to directly ground the rear light fixture with no benefit.

Again, this truck has not moved since they were all working last week.

Thus my confusion!

hmm, is there a connector farther up along the frame that may have gotten corroded a bit? If you are sure you have good ground to the tail light housings, then it may be a break in the wires somewhere. (seems strange though). When you tested voltage, was the - lead on your meter connected to the wire running up to the - post on the battery?

Found it!

I have current on the switch and at the brake light switch. I have current on the wires after the brake light switch, but midways back I found a terminal connector for both the tailight wire and brake light wire. I had current on the vehicle front end wire leaving the switches going into those terminals, so the terminals which were wrapped with electrical tape must need replacing. After doing so, I had both tailights and brake lights. It's just strange how the electrical gremlins do their work without any vehicle activity or movement.

Thanks to everyone who contributed!

sweet! glad you found it!

Cuda wins the prize!

One thing to keep an eye on are mice and squirrels. The love old vehicles that don't move for awhile, and the insulation on the wires. Can't tell you how many cars we have seen at our shop that have "fed" varmits. Are you in WNC?

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I can assure you there are no varmits! This was just a case of a metal connector that expanded and contracted with garage temps and finally lost connectivity.

And to answer your question, yes!