A/C compressor not engaging randomly
Thread Starter
Junior Member
Joined: Feb 2012
Posts: 30
Likes: 1
From: Toronto, Ontario
2017 Mercedes S550, 2015 Mercedes GL350
A/C compressor not engaging randomly
Recently after a repair to the alternator, glow plug module I started having A/C problems. Invoice also indicated they replaced a fuse box. The A/C compressor just doesn't come on. After you drive the car for maybe 20min it starts to cool all of a sudden. Sometimes it's good for the rest of the day even after restarts. Other times it will work for a while and then you will hear the fan start to speed up again and the air getting damp and warmer. Turning it off/on does nothing. Just have to wait until it feels like coming on again. Usually doesn't work at all when car cold first thing in the morning. Seems to work better after the engine has run for a while on hot days, although last 2 days were cooler out and it worked first thing in the morning. Going to dealer tomorrow but am afraid it will work when they look at it and not sure if A/C problems would set any codes in the computer.
MBWorld Fanatic!
Joined: Dec 2004
Posts: 4,268
Likes: 253
there will be codes for low pressure in the system. you either sprung a leak or a pressure sensor is bad.
it is also possible that the relay for engaging the ac compressor clutch got damaged when they replaced the fuse box.
it is also possible that the relay for engaging the ac compressor clutch got damaged when they replaced the fuse box.
