My mother-in-law's battery in her 2008 Chevy HHR died over night. She thought it was the dome light and actually turned out to be the third brake light. Yes, it can and will stay on with the key out and car off. Brake switch/sensor must have been stuck or something because after pumping the pedal a couple of times it went out and has stayed off and only comes on when driving.

So, I took her battery out to charge it. Charged it back up, cleaned the posts and cables and took it for a drive.

Now the list of things that no longer work after simply removing the battery from the spare tire well charging it and reinstalling it:

• power steering warning
• tpm warning
• CEL for
• - speedo doesn't work (tach, gas and temp do)
• - won't shift out of second

The battery has been tested by two separate parts stores and it checks out good. My charger also shows it as being full. I've checked all fuses related to power steering, cluster, etc.

I looked through the stickied threads but didn't see anything that matched this. We did jump it once and did it properly using the positive tap at the fuse box and the strut nut. I checked fuses just in case and all including the 60a power steering fusible link and nothing is blown.

Hoping someone might have a solution.

 

Hello to you Sir, to the forums!!

It may help if you were to post up the actual CEL codes, often the description given by the parts store is misleading or generic. Also, if they gave you a printout of the battery test, that may show us something.

Sounds like you also may have a bad Brake Pedal Position (BPP) sensor. It's a plastic electrical device on the brake pedal arm.

 

On second thought, if the BPP sensor were bad, it would probably have illuminated all the brake lights. Have the third brake light bulbs been replaced? with LED bulbs?

EDIT: A couple more questions.
Does the cruise control work?
do the side brake lights work?

 

Welcome to the site, please check the ground connections

https://www.chevyhhr.net/forums/how-...cations-56504/

 

The CHMSL is on a completely different circuit than the other brake lights.

Many times people jump start properly but if the red clamp even touches the TCM you have major problems. That is very easy to do especially if the plastic hood has gone missing.

The other thing to look at is the 60 amp fuse next to the battery.

 

Did you try swapping the battery with a different one?
Just a thought.