Brake lights only show on center 3rd high stop tail lamp
I have a 1999 suburban and the brake lamps don't flash on the sides of the car, only on the 3rd high center stop tail lamp. I believe this problem started after using the emergency flashers and the emergency flasher button is stuck on the steering wheel. Does the emergency flasher block the signal? Some other cause? If this is the problem how can I unjam the flasher switch without breaking it? Thanks for any assistance!
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Kevin , this is a very complex way of stoplamp control , I will post GM service Description and Operation of how they work an let you deside if you want to tackle this ! Do the center high mount brake lights work ?
The brake pedal position sensor is a resistive device used to sense the action of the driver's application of the brake pedal. The brake pedal position sensor provides an analog signal that will increase as the brake pedal is pressed.
The brake pedal position sensor receives both a 5-volt reference voltage and a low reference signal from the electronic brake control module (EBCM). When the brake pedal is pressed, a variable signal is applied from the brake pedal position sensor to the EBCM through the brake sensor signal circuit. The fuse block left rear supplies battery positive voltage to the bass relay switch through the BASS fuse. One side of the bass relay coil is permanently grounded at G402. The EBCM supplies voltage to the bass relay coil upon receiving the signal from the brake pedal position sensor. The switch contacts of the bas relay close and battery positive voltage is applied through the bas relay switch to the center high mounted stop lamp (CHMSL), and to the turn signal/hazard flasher module through the stop lamp switch signal circuit. The ground for the CHMSL is applied from G402. The turn signal/hazard flasher module then supplies voltage to the left and right stop lamps in the tail lamp assemblies that have ground at G401 and G402. For export vehicles the stop lamps receive battery positive voltage directly from the bass relay.
There could be a code stored in the EBCM - electronic brake control module - DTC B3903 Stop Lamp Relay Circuit
DTC C0278 Brake Pedal Position Sensor Not Calibrated
there are several other codes that pertane to the brake lights . you could try Replaceing the bas relay !
Fuse Block - Left Rear
In the passenger compartment, under the left side of the rear seat at carpet.
Where the brake lamp attatches to is called a tail lamp assembly,some call it a rear light module,they are sold in pair and they do fail,you did the brake switch and the combination switch,either the wire is disconnected some how or the lamp assemby both side failed,
No, it is not the brake lamp switch. If the brake lamp switch was not working, the high mount (3rd) brake lamp would also not function. Chevrolet trucks are notorious for bad tail lamp circuit boards.
Disconnect the electrical connector from the circuit boards. Check for power at the circuit board connector (with the brake pedal depressed) on each side. The brake/turn lamp circuit for the left side is the YELLOW wire. The brake/turn lamp circuit for the right side is the GREEN wire. If there is power at the connector, check the GROUND (BLACK wires) to make sure they are getting a good ground. If the power and ground circuits are OK at the connector, replace the circuit boards.
NOTE: DORMAN makes a kit that includes circuit boards for both sides it is DORMAN Part Number 70001
If there is no power on the YELLOW and GREEN wires at the circuit board connectors, the most likely cause would be a defective turn signal switch.
check the lt blue wire at upper lamp,(under trunk lid trim panel) for 12 volts when brake is applied. if no voltage,check same color wire at brake lamp switch for voltage.(by brake pedal).if no voltage replace stop lamp switch asm. if voltage is detected at rear by lamp then replace CHMSL asm.(center high mount stop lamp). this lamp is made of many LED's,if some work and some don't you will need to replace lamp asm. can be repaired by a trained GM tech, possibly. there is no seperate fuse or relay for this lamp,only a stop lamp fuse.
I suggest to check your tail lights. sometimes if they go out, the cruise control will not work. Oh and also, what i did when this happened to me, I checked under the brake pedal and pushed and pulled the little button that activates the taillights and it worked again. It may have gotten stuck..
The brake light fuse may have popped..
ALSO: -- There seems to be a recall for this..
CERTAIN PICKUP TRUCKS MAY EXPERIENCE THE PERMANENT LOSS OF BRAKE LAMP FUNCTION OR BRAKE LAMPS THAT ARE ILLUMINATED AT ALL TIMES. THE CENTER HIGH-MOUNTED STOP LAMP (CHMSL) IS AFFECTED IN BOTH INSTANCES. ALSO, IF EQUIPPED, THE CRUISE CONTROL WILL BECOME INOPERATIVE. ANY TRAILER BRAKE LAMPS WHICH ARE CONNECTED TO THE VEHICLE'S BRAKE LAMP WIRING WILL MIMIC THE VEHICLE'S BRAKE LAMPS WHEN EITHER CONDITION OCCURS.
need to know if your third brake light up high is working or not.if it isn't,you need to check the brake light switch on the brake pedal with a test light,one side hot all the time,the other side should turn hot when brake pedal is pushed.