2007 SL550 AC clutch always engaged even with AC or fan off
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2007 SL550 AC clutch always engaged even with AC or fan off
Greetings everyone! This is my first post to this forum. I have performed many different types of repairs to different brands but I am still new to MB vehicles. I have a 2007 SL550 that only has over 40,000km on it but has a few little issues. It’s usually stored indoors and is a wonderful vehicle. I like when everything runs flawlessly. I’ve been noticing a couple sounds coming from the front and when trying to diagnose it seems like one of the noises was coming from a fan belt pulley. One other thing I noticed was that the AC clutch was always engaged even though the AC system was off, not in defrost function, even with the HVAC fan being turned off.
I ordered a new set of idler pulleys, tensioner and drive belt. When I had the drive belt off I inspected the AC compressor and everything seems fine. Pulley turns fine, so weird sounds or anything binding. I installed the new pulleys, tensioner and drive belt, put this back together and tested everything again and the AC compressor stays engaged. When I have the fan blowing, it gets cold and works fine but when I turn the AC off or fan off it seems like somehow the AC clutch is still getting signal to activate even though nothing from the control panel is telling it to turn on. Same thing happens if I turn the HVAC off, turn car off and start the vehicle again. The AC clutch engages and stays engaged.
Does anyone have any suggestions of what to check or any idea what can cause this issue? Any recommendations of what to check? Any potential common trouble spots?
Thanks in advance,
Chris
I ordered a new set of idler pulleys, tensioner and drive belt. When I had the drive belt off I inspected the AC compressor and everything seems fine. Pulley turns fine, so weird sounds or anything binding. I installed the new pulleys, tensioner and drive belt, put this back together and tested everything again and the AC compressor stays engaged. When I have the fan blowing, it gets cold and works fine but when I turn the AC off or fan off it seems like somehow the AC clutch is still getting signal to activate even though nothing from the control panel is telling it to turn on. Same thing happens if I turn the HVAC off, turn car off and start the vehicle again. The AC clutch engages and stays engaged.
Does anyone have any suggestions of what to check or any idea what can cause this issue? Any recommendations of what to check? Any potential common trouble spots?
Thanks in advance,
Chris
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