DAStx435

I have a 2011 HHR LT that replaced a 2006 HHR LS. The cruise control and the “Center high mount stop light” (CHMSL) does not work. Also I am having a power drain from the battery. The tail/brake lights were LED lights. I have replaced those with the filament bulbs. I also have replaced the brake switch on the brake pedal. Occasionally I will go out and look at the HHR and the center high mount stop light will be lit. I have done a lot of reading and troubleshooting these problems and I am at a loss. I have also cleaned all of the battery connections from the battery to the fuse box. Any help would be greatly appreciated on what else I can do. In advance thank you.

Oldblue

Welcome to the site, are the centre brake lamp bulbs LED?
Did you remove any resistors when you changed the LED brake lamp bulbs back to filament?
Are you grind wires near the tail lights clean and tight?

DAStx435

Thank you Oldblue, they were filament bulbs. One was burnt out, replaced them with equivalent LED bulbs. Have now put the filament bulbs back in. Acts same with filament or LED bulbs. The ground wire is near the tail lights seams tight. Going to try to run a ground wire from that ground location as a test.

DAStx435

I use the meter to check the voltage at the third stop light voltage was zero with brake on. Tested it to ground and the voltage was still zero. Checked the lower brake lights when pedal depressed was 12 V. When using the flashers the voltage was 10.4 V. Turn the auto on and off in the third light stayed on with car turned off or on, and upper brake light started working was at 10.8 V. Turned the car off and on the upper brake light stopped working. On the upper brake light it is a lite blue color with the ground. Where does the lite blue wire get its signal from?

Oldblue

The BCM

DAStx435

Update, Upper brake light is not controlled by brake pedal. Start auto and press brake pedal and nothing. Turn ing off and the upper brake light goes on. Stays on until you restart the car...... There is a 50/50 chance of it going on when car ing turned off. Any ideas????? Could the BCM need to be reprogrammed? I did reseat the connector in the BCM Lower connector..

Oldblue

Try a battery lobotomy, disconnect the negative cable at the battery for 30 minutes, then reconnect the cable . The 30 minutes will give time for the computer to reset.

DAStx435

I tried the battery lobotomy (for 50 min) did not fix the problem. Now when I step on the brake and turn the key off the upper brake light comes on and stays lit until I restart the car. Any Ideas??

donbrew

My guess is that somebody tapped into a wire that they should not have.

I'm thinking they tapped into the hot side and now whatever they hooked up is grounding the high light, instead of the BCM doing that.

DAStx435

donbrew, Thanks..... I have looked on the Light Blue (HOT SIDE) and the Black (Ground Wire) don't see any place someone could have tapped into it. There are no extra's added into the auto that would require power. Any other ideas ???? I have looked at all the places I can see to make sure the harness is not grounding.