So I have this bizarre problem with my 5 cylinder 2006 H3. It involves the O2 sensor, the driver's side seat heater, the radio, and the status of the car. If the car is on before the heater is turned on, then the check engine light does not come on. However, if the heater is on before the car is turned on then the check engine light comes on. Always the diagnostics say it is the O2 sensor attached near the catalytic converter. And now this summer the engine light came on and the seat was off, but the radio is now dead. Same thing again O2 sensor, only this time we can't get rid of the fault. Any thoughts?

 

Most electrical gremlins start with bad or loose connections.

Start with making sure that your battery connectors are tight. The OEM connectors are crap and have been proven to be the main culprit in many electrical issues.
Most of us at some point replace them with better quality connectors and many problems disappear.

Do that before going any further.

 

I agree with Bunger's step one.

Remember, your truck is 8 years old, radios do puke. After step one, I would check fuses and see that the radio is getting power to confirm if it is a dead radio, or a short in the harness.

May I ask, do you have a sun roof? Has your passenger side front floor ever been wet?

 

Thank you for the advise. I will check the connections. Yes I have a sun roof and lights on the roof as well. As for the passenger side front floor ever being wet, most likely but we do have front mats.

 

Thanks, I will check the connections

 

Your question about wet floor caught my interest. The floor is not wet. But, I'm thinking that it might make sense to do some preventive maintenance. How do I find the instructions on clearing the drain?

 

Umm, use the search feature.

Here's your one and only free pass:
https://www.hummerforums.com/forum/h...n-tubes-28548/