Brake light led replacment problem *weird*
05-02-2017, 01:45 AM
#1
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Brake light led replacment problem *weird* I have a weird situation I have replaced all of my bulbs to led but just noticed recently when the engine is on (autolamps on) the brake light stays on but the third brake light led works normal, when the autolamps or headlight switch is off the brake lights works normal. I had these in my car for years only noticed it recently. Is the brake light controlled by the brake pedal switch or is it bcm controlled.
05-02-2017, 02:12 PM
#2
None of the brake lights (or any other exterior lights for that matter) are controlled by the BCM. The BRAKE light in the instrument cluster is controlled by the parking brake switch via the DRL module. It can also be activated by a switch in the master cylinder that indicates fluid problems. The brake lights on the rear of the car are controlled by the brake switch at the brake pedal without any electronics involved - battery power runs through the switch to the lamps and then to ground.
Do your other lights work normally? The symptoms you describe could indicate a bad ground causing current to back feed through the circuit. The first thing to do would be to replace the LED bulb with a standard incandescent bulb to eliminate the possibility of it being leak-down current.
Do your other lights work normally? The symptoms you describe could indicate a bad ground causing current to back feed through the circuit. The first thing to do would be to replace the LED bulb with a standard incandescent bulb to eliminate the possibility of it being leak-down current.
05-13-2017, 11:58 PM
#3
This is just a theory but...
Brake bulbs are dual filament bulbs. One comes on when the headlights are on (either via switch or autolamps) to make you more visible to cars behind you at night. The other comes on when the brake pedal is pressed.
It sounds like the LEDs are seeing the signal for the headlights and coming on at full brightness. I'm assuming they get no brighter when you step on the brake?
Brake bulbs are dual filament bulbs. One comes on when the headlights are on (either via switch or autolamps) to make you more visible to cars behind you at night. The other comes on when the brake pedal is pressed.
It sounds like the LEDs are seeing the signal for the headlights and coming on at full brightness. I'm assuming they get no brighter when you step on the brake?