Quote:
Originally Posted by andrewwynn
BMW uses PWM for setting voltage levels; set your dash to full brightness and see if things change.
Do you have a voltmeter that shows duty cycle? If not at least measure ac on any lines that should be DC.
If you are using a "12v" line to power something you are likely tapped into a 14.4v line that is chopped up into 83% on 17% off. That would definitely cause terrible hum
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Yes the noise and static was getting worse with turning on the switch dial.
I do have a multimeter with duty cycle but haven't tested with it yet.
I wired the relay in the following way:
Not sure if it was a bad relay or if that wire was using pwm and causing issues.
The fact that the whine was getting worse with turning on the headlights led the tech to believe the noise was caused by headlights, fog lights etc. He disconnected them all but nothing changed. I think at this point it wasn't actually a whine but rather a high pitched static.
At this point he worked on the car for so long that the battery discharged and wouldn't start the car, so whine issue could not be verified.
He kept working on that light switch for hours, trying to wire things up with another relay etc...
In the end he couldn't fix the problem.
So yesterday I just wired it back as per factory.
If there's a possibility the relay was causing problems, I really don't need those parking lights when car is remote started.
07-04-2022, 12:20 PM
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