Cadillac Repair: 1986 cadillac tail lights problem, trailer hitches, fuse box

Question
I have an 86 cadillac deville. The tail lights don't work when I have the headlights on. They work for turn signals and brakes. I checked all bulbs and fuses, all good. If there is a short somewhere, how can I find it?

Answer
Hi Shawn,

Tail lights are not on the same circuit as the brake lights and turn signals.

Turn the head lights on and see if the side markers work. If not, you have a problem somewhere between the junction block at the firewall in the passenger compartment on the driver's side and the tail lights.

I know normally these cars did not have trailer hitches, but occassionally they did. Trailer wiring is known for problems.

You said you checked all the bulbs and fuses or did you? It does not matter if the brake and t/s work. Bulb filiment for tailight could still be bad. If you pull the bulb, you will see the broken filiment right away. Chances of having two bad bulbs are rare, but possible.

You may want to look at the owners manual as well to see if there is another fuse box. I know on many caddys, they had another in the trunk.

Rob