Brake Lights - CHMSL Only
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Brake Lights - CHMSL Only This is a new one for me.
On our 2000 Firebird - When driving the car and applying the brakes, only the CHMSL illuminates. All lights work fine when turned on, and the 4-ways illuminate as they should.
Is the brake light switch specific to the lower harness and not the CHMSL? If so, that is probably my issue.
Anyone have this before?
On our 2000 Firebird - When driving the car and applying the brakes, only the CHMSL illuminates. All lights work fine when turned on, and the 4-ways illuminate as they should.
Is the brake light switch specific to the lower harness and not the CHMSL? If so, that is probably my issue.
Anyone have this before?
Last edited by Paul94Z28; Oct 25, 2022 at 03:47 PM. Reason: add vehicle detail
Thread Starter
Teching In
Joined: Jan 2018
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Additional Details - both same result:
Ignition Off - parking lights and 4 ways work as they should. No lower brake lights when pedal is depressed, only CHMSL
Ignition On - parking lights and 4 ways work as they should. No lower brake lights when pedal is depressed, only CHMSL
I have one bulb that may have one of its filaments out - will change that bulb/socket (if needed) out and report back
Ignition Off - parking lights and 4 ways work as they should. No lower brake lights when pedal is depressed, only CHMSL
Ignition On - parking lights and 4 ways work as they should. No lower brake lights when pedal is depressed, only CHMSL
I have one bulb that may have one of its filaments out - will change that bulb/socket (if needed) out and report back
Joined: Nov 2003
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From: Jacksonville, FL (originally from Toronto Canada)
This may sound strange but your problem may be your turn signal switch. Because Firebirds use the same lamps for both stop and turn signals, the turn signal switch has to be able to split the signal so that one side can flash while the other remains solid when stopped with the turn signal on. The CHMSL gets powered directly off the brake switch but the power flows from the brake switch through the turn signal switch to the other brake lights.
If you have a multimeter or test light, you can test for power output on the dark green and/or yellow wires (right and left respectively) at connector C216... the black flat 11-pin connector (only 10 pins used) attached to the steering column. Don't unplug the connector - just insert the probe into the back side of the connector with the appropriate wire. If you don't get power on those two wires when the brake switch is pressed then check the light blue next to the dark green. That's the power input from the brake switch. If you get power there when the brake pedal is depressed but you're not getting power on the yellow or dark green wires then you know the turn signal switch is the problem. If you don't get power on the light blue then you have a break in that wire somewhere between the brake switch and connector.
Those are the only two possibilities based on your symptoms. The yellow and dark green wires could not have a break in them because your turn signals and hazard flashers work using those same wires. It could not be a brake switch problem or fuse because the CHMSL works and the wiring splice between the CHMSL circuit and the other lights is after the brake switch, so power is getting through the brake switch.
If you have a multimeter or test light, you can test for power output on the dark green and/or yellow wires (right and left respectively) at connector C216... the black flat 11-pin connector (only 10 pins used) attached to the steering column. Don't unplug the connector - just insert the probe into the back side of the connector with the appropriate wire. If you don't get power on those two wires when the brake switch is pressed then check the light blue next to the dark green. That's the power input from the brake switch. If you get power there when the brake pedal is depressed but you're not getting power on the yellow or dark green wires then you know the turn signal switch is the problem. If you don't get power on the light blue then you have a break in that wire somewhere between the brake switch and connector.
Those are the only two possibilities based on your symptoms. The yellow and dark green wires could not have a break in them because your turn signals and hazard flashers work using those same wires. It could not be a brake switch problem or fuse because the CHMSL works and the wiring splice between the CHMSL circuit and the other lights is after the brake switch, so power is getting through the brake switch.
Thread Starter
Teching In
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Thank You WhiteBird00!
Apologies for the delay in updating, but it has been a busy time of year.
I was able to confirm that it was the turn signal switch that was the problem. I had some additional issues with my tilt column that required a rebuild. It is in and done and we have all lights again.
Apologies for the delay in updating, but it has been a busy time of year.
I was able to confirm that it was the turn signal switch that was the problem. I had some additional issues with my tilt column that required a rebuild. It is in and done and we have all lights again.
