I had the most horrific drive home from work tonight. I tried searching to see if this problem was listed but don't even know what to call it, so let me tell you what happened and I truly hope someone knows what might have caused this.

First, we were under a tornado watch and tornadoes had touched down in our local area so we were not allowed to leave work till the warnings were lifted. I tell you this because I don't know if that could remotely have had anything to do with the issues that I had.

I have about a 25 mile drive to get home. About a mile from work, all of a sudden my OnStar Phone came on and told me to tell it what number I wanted to dial. Extremely weird as I've not used the OnStar phone in years and I had not touched anything to turn it on. I said CANCEL and it went off. So, a few more miles down the road, it happened again and this time after I would say CANCEL, it would keep repeating itself, tell me thank you after I canceled then come right back on. THEN the scariest part, especially at about 1AM when it's pitch black as I live out in the country. I had my brights on and suddenly my lights would go off, then come back on, me touching NOTHING. Then I noticed it was going off like bright, regular, then off, then back to bright, regular and then off. Then it would be ok for a mile or two, then do it again. Super scary as I could not see two feet in front of me. So, I put my emergency flashers on just in case anyone else was on the road so they could see me. The lights things happened again. This time, about 2 miles from home, I did an experiment and turned the brights off and just had the regular lights on and the lights did not go back out, but I don't know if it's a coincidence or if the brights being on was the problem.

I had OnStar do a diagnostics on it when I was almost home and they said they showed no error codes with anything electrical. She said "possibly" something might reset itself when I turn the vehicle off and then back on, but of course I was not going to try that as I did not want to be stuck on the side of the road in this weather.

Thank you for any help and advice, this forum is always helpful!

 

Have you replaced your battery clamps. The OEM ones can cause weird problems.

 

No, I haven't. Just weird that this happened during really bad weather and had never done anything remotely like that before. Thanks for your reply, I'll look into that.

 

Do you have a sunroof? If so, ever have the passenger side floor wet???

 

Yes, I have a sun roof and never noticed the passenger side being wet.

 

Might want to check your sun roof drains, when they get plugged up with crud, water leaks inside the passenger A Pillar and can get the BCM wet, which can cause all the things you described and much more.

Do a search here for A fix for sun roof drains .... something like that, there is some good info on what to do.

Found it, take a look: https://www.hummerforums.com/forum/h...n-tubes-28548/

 

Might just be the switch or harness loose on the switch also. If your switch is like mine the but ten to make calls is next to the dimmer and fog light switch.