Ok, I just purchased a clean 05 R53 with 61000 miles on it, whenever it is on high in a/c auto mode, radio on, it will freak out. A/c shuts off, radio shuts off, dash lights come on, seat belt, air bag, engine loses power. It will only do it for a few minutes, then works fine with the exception on the seatbelt light stays on. If I turn it off an on, all is fine. Starting the car was sluggish so I replaced the battery and reset the ecu. Still does it. If I manually command the a/c and not go over 4 bars on the fan, all is good. Just wondering if anybody else had the issue and found a problem. I read other issues on the forum but all were slightly different. I might think it has a ground issue. Any thoughts, thx

 

Check everything out around and in the fuse box. With electrical things like this it's usually something in that area or the battery and since you already replaced the battery, I'd start looking there. Another idea could be the alternator as it provides your car with a constant source of electricity while the engine is running. Over time, the alternator can begin to fail and start causing trouble with the various electrical systems in the car. If you suspect alternator trouble, you need to check to see that is operating correctly, and is indeed the cause of the problems with your charging system. Sometimes bizarre electrical problems can be caused by a number of faults other than the alternator. It's important to troubleshoot the system prior to replacing your alternator. Just an idea. You can read more about it and how to replace it here. Maybe someone will have other input as well. Good luck!

-Luccia

 

Just a hunch...
Do you have a sunroof....if you do you might have a water leak from a sunroof...
Sometimes the drains get disconnected..the water runs down the sidetubes...
And gets the bcm wet on one side...the fuse box wet on the other..corrosion sets in..have seen a few fuse boxes replaced due to corrosion on the back...

 

Thanks for the replies, I'll have to check the alternator with my meter to see what it's putting out, as far as bcm, I do have the moon roof but I live in So Cal were we don't get much of , what did you call it? Rain? but I will definitely look at those areas as well...