'91 Chevy Lumina, brake lights remain lit even when car is shut off. Can't figure out why.

Follow the link for free diagrams of US sold makes http://bbbind.com/free_tsb.html

This will either be a fuse or the brake light switch which is on the pedal it's self. More likely the switch as these are fickle at best.

on your brake pedal there is a switch that controls your brake lights over time it comes to lose just enough for the switch won't come in contact with the pedal

your door pin switch is most likely bad. it is what turns it on and off.

1993-96 Vehicles
See Figure 2

Fig. Fig. 2: Brake light or stoplamp switch mounting-1995 vehicle shown

1. Disconnect the negative battery cable. -96 vehicles, remove the driver's side instrument panel sound insulator panel.
2. Detach the switch electrical connectors.
3. Remove the switch from the brake pedal bracket.

To install:

1. Position the switch to the brake pedal bracket.
2. Attach the electrical connectors.
3. If removed, install the driver's side instrument panel sound insulator panel.
4. Connect the negative battery cable.

There is a brake light swich along the brake peddle that need's to be adjusted. Quick and easy fix.

test and replace the brake light switch, it is located at the top of the arm the brake pedal is attached to.

The ground wire in the trunk area, coming from the brake light harness, might have come off or really loose. Hope this will get your lights working again. Best wishes.

This is a classic example of turn signal switch failure. On GM vehicles with a multi-function turn signal switch and combination stop/turn/tail lights (all rear lights are behind red colored lenses except for back-up lights) The brake light power is routed through the turn signal switch. This makes it possible for the right rear light to function as a stop light while the left rear turn signal flashes, and vice-versa. When the contacts fail to remain constant the brake lights, and turn signals can become intermittent. The proof that the brake light switch is functioning correctly is that the high center (cyclops) brake light functions properly. Wiring integrity is verified if you can prove that turn signals operate, but that can still be intermittent with this complaint, BUT if you use your hazard switch to turn on all the signals at once, you can verify wiring integrity. This is because the turn signal, and the brake light use the same circuit, and bulb filament in the rear lighting assembly. If any Hazard lights fail to function, check bulbs first, then retest. If all Hazrd light flash correctly and reliably, bulbs, sockets, and wiring have proven integrity, and the turn signal switch is the remaining component in the system which needs to be tested. Unfortunately, this switch requires disassembly of the steering column for service, testing or replacement. If you have never disassembled, and successfully reassembled a GM tilt steering column, I would reccommend professional assistance.

i would check the bulbs first. then continue to the brake switch