2008 Grand Prix Base - Multiple problems

[dennis7474]

I apologize if this has been discussed previously. I did try to search for the topic and got a wide range of results, but not exactly my problem. If I missed the correct thread, please point me to it. I'm not looking to bother anyone.

I have the following issues when shutting my car off:

Horn goes off (sometimes once, sometimes multiple honks)
Wipers start
Trunk opens
Date and time default to January 1 and 12:00
Lights flash

It doesn't always happen, and when it does, it can be a mixture of any of the issues above. Sometimes it's just the horn and trunk. Other times just the date and time. Others everything happens.

My check engine light isn't on. I do not have problems starting the vehicle.

Nothing has been replaced on the car recently.

I'm at a loss as to what could cause this. I just recently went over 107k miles.

Anyone have any ideas as to what could cause something like this happen?

Thank you in advance.

 

[melsg5]

Just a guess would be an issue with the BCM, body control module, or it's wire harness. You would need to find a shop capable of running diagnostics on the module, it may have a code stored.
You have checked and cleaned the battery connections?

 

[dennis7474]

Yes. I apologize for not including that information in the original post.

Checked the batter and cleaned the connections (there was some minor build-up around the terminals).

Thank you for the advice. My next step will be finding a shop that can check the BCM.