Tail lights quit working - 1993 Mercury Grand Marquis

Check your fuses. I had the same problem with a 90 Honda civic. Dash lights went out, tail lights also went out. Replaced 1 fuse and all came back on.

Sounds like the fuse for the Tail Lights Is Blown.

The switch is bad, it can't be serviced, it has to be replaced

check the fuse, the tail and dask lights are tied together but you may have a short in the system that caused the problem.

Auto light shut off is a relay that is basically a timer.
Replace it .

The tail lights working would not necessarily mean that the brake light bulbs are good. If they are the type that have a double filament (ie: one filament for the tail light and another filament for the brake light ) the brake light filament could be bad and the tail lights still would work. If they are either single filament type bulbs or double filament type, I would check the bulb, fuses, and contact switch on the brake pedal.

check your fuse box ..look for burnt fuses.

I found out that if I pull the headlamp switch a little bit that the tail lights will then work for some reason

Your tail lights work off a fuse called park lights. No relay involved. Do you headlights come one. Please go premium so I can get paid for info. If ths has helped, please post as such.TY

Tail lights acting insane?

We had the same issue with our 2000 Pontiac Montana. Brake lights, turn signal lights, running lights, back-up lights and emergency flasher didn’t work at all or operated at random. The cause: poorly designed aluminum contacts on the tail light circuit board and wiring harness connector arced over and disintegrated with normal use.

Pull the tail lamp assembly, remove the electrical connector and look for burned contacts on the connector plug and the connector socket (they call this long plastic piece with the socket the circuit board: it includes the four bulb sockets. Replace the circuit board and the wiring connector.

You can DIY this job with basic auto mechanical/electrical skills and tools. The two circuit boards and the two connectors set me back $230 (2009 cost) for new parts. The electrical contacts on the factory replacement parts are improved.

I needed a T-30 torx driver to remove the tail light assembly (you need this to change out bulbs, too), wire cutters, wire strippers, electrical tape and an electrical lug crimper to do the job.