Hello, I am having a problem with my taillights on my 72 cutlass supreme.I'm not sure how their suppose to be wired but on the left side the brake light comes on ,on the upper part of the light assembly.On the right side the brake light comes on,on the bottom side of the light assembly.Does anybody know what's going on?

 

First thing would be to check the bulbs, all four should light up with the brakes. There are two filiments in each bulb, be sure they are both good. That would be the easiest thing to check and if the bulbs are all good then check the sockets and start tracing the power back from the light assemblies back toward the front of the car. John

 

All 4 sockets work.It's just the right side only lights up at the top and the left side lights up at the bottom of the assembly.

 

If your sure the bulbs are good, and your sure the sockets are good then you need to go to the wires that the sockets plug into and check to see if they're getting power when you apply the brakes. I was 99% sure your problem would be at the socket or bulb since some of the lamps light up but not all of them. But you may have a problem in the wiring between the bumper and the brake switch. That's what you'll need to do, start at the bumper checking for power and work your way back toward the front of the car until you find the point where your test light lights up for that bulb that's not working. If the car has or had a trailer hitch check for wire splices that may be bad, that's something else that could cause the problem. John

 

I would have to agree that it is either the bulbs or the wiring. Sometimes the bulbs will fool you and look like they are good but are not. I would start out by replacing the bulbs that are not working or switch in one that is for one thats not and go from there. Personaly I would start out with all new and and be sure (hopefully) that all are good.
Good luck,
Doug

 

Thank you for the suggestions.I am going out to the garage to try those things right now. Are all of the lights on the top and bottom suppose to come on when you press the brake pedal?

 

Yes, the lights on the top and bottom on both sides should light up when the brakes are applied.