Nick Stokes

Hey all! First post here. I've been using MBWorld for my 4 different vehicles for many years now, but have never made an account because there was never anything I could't find the answer to. Until today! So today I was Uber driving in my W211 E55, and I had the radio volume down because I had an older passenger riding along. I heard a faint, extremely high pitch sound, identical to a "dog whistle" coming from somewhere around the climate control module / stereo region. When I got home, I played around with turning on/off the climate control, the stereo, the engine, the headlights, interior lights etc. etc. This noise stays ringing no matter what, as long as the key is in the second-click position. It is not engine bay related as it is present with the engine off. It is not heater/blower related because it persists with all climate control off. I know for certain that it is electrical related. I want to say that it is the climate control module's electrical parts because I unfortunately had an air freshener that was fastened to the vent directly above the climate control leak its juice into the seams of it, and now it wont display the interior climate. The screen wont display anything. I'm thinking/hoping that is the sole issue here. I'm looking to buy a used climate control module off of eBay or something to avoid the stealership. Praying that it will eliminate this ungodly noise as well.

Anyone have any thoughts or ideas on what else this may be? Every reply is appreciated. Thanks!!

jimbo1763

That sort of stuff is hard to find. It may be possible that it is caused simply by power going to a particular device or a capacitor, and not necessarily just because that device is switched on. However, your surmising as to the climate control sounds pretty good under your circumstances. It would be nice if you could simply remove the climate control module first and then see if the noise continues when you turn the key.

cmriv

post a video

rapidoxidation

Narrow down which system it is by pulling fuses (one at a time) until the sound stops. At least you'll know what circuit you're dealing with.