I have an 88 Cadillac Fleetwood d'elegance and I've had trouble with the taillights for a while now but it was always that I couldn't run the rear defroster with the lights on or it would blow the fuse. A shop changed the ball joint on my car and reconnected the battery and ever since then my tail lights wont work at all. It keeps blowing the fuse. I read somewhere that the cigarette lighters are on the same fuse so I pulled all those and put a new fuse in and they worked but once I closed my glove box the fuse blew again and they wont work. Now if the glove box is open it wont blow the fuse but the lights wont come on. I've looked for a short and cant find one anywhere and I'm trying to not have to put it into a shop but I'm not mechanically inclined so I think I may have to, unless you can help. Thanks
Do you have a trailer harness? That commonly is a problem. Tail lights are linked with the dash lights, but a separate circuit. Its common the dash lights do not work when the tail lights do not work.
You definitely have a short. The harness plugs in at the firewall under the dash and runs under the carpet to the rear of the car. There should be no issues there leaving you with a bad trailer harness that can be snipped off, separated and taped, or a bad bulb or socket.
A ball joint has nothing to do with your problem and I don't have any idea why the battery was disconnected to change a ball joint.
Your problem is either in the trunk, bulbs, sockets or a hidden trailer harness.