1995 SL500 compressor and high speed fan issues resolved!

[Gusfazekas]

You might recall after I swapped the compressor on this '95 SL 500 that my high speed fans were on from start-up and the A/C compressor clutch would not activate. Not long after I had both the check engine light and the ASR light come on, both within about 10 miles of driving. I replaced the coolant temp sensor, MB techs at the dealer and this site thought that it had become defective and caused the fans to activate and override the A/C clutch preventing it from engaging. I replaced the coolant temp sensor but no change. At the suggestion of MB doc., I checked the wiring harness and it was shot, same ailment that others have suffered, ie.. brittle degraded wires shorting out. Well I changed the harness and the ASR light and check engine light disappeared but the A/C problem persisted. At the suggestion of another MB tech., I bypassed the green pressure sensor on the drier and the compressor engaged but the fans kept on blowing. Got me to thinking that I had connected the wires to the wrong sensors. Well, sure enough, this "dummy" ME, misconnected them. A/C and the fans now work fine. Lesson learned, check the wiring and take pictures before you put things back together. Something this simple "stumped" at least 5 MB techs over a period of two weeks or more. Thanks to all for their help and advice with my problems, Steve

[scottmcphee]

Originally Posted by Gusfazekas

You might recall after I swapped the compressor on this '95 SL 500 that my high speed fans were on from start-up and the A/C compressor clutch would not activate. Not long after I had both the check engine light and the ASR light come on, both within about 10 miles of driving. I replaced the coolant temp sensor, MB techs at the dealer and this site thought that it had become defective and caused the fans to activate and override the A/C clutch preventing it from engaging. I replaced the coolant temp sensor but no change. At the suggestion of MB doc., I checked the wiring harness and it was shot, same ailment that others have suffered, ie.. brittle degraded wires shorting out. Well I changed the harness and the ASR light and check engine light disappeared but the A/C problem persisted. At the suggestion of another MB tech., I bypassed the green pressure sensor on the drier and the compressor engaged but the fans kept on blowing. Got me to thinking that I had connected the wires to the wrong sensors. Well, sure enough, this "dummy" ME, misconnected them. A/C and the fans now work fine. Lesson learned, check the wiring and take pictures before you put things back together. Something this simple "stumped" at least 5 MB techs over a period of two weeks or more. Thanks to all for their help and advice with my problems, Steve

Please post a picture, or include the manual pages with the highlighted error. I think a visual on this would help a lot.

[Gusfazekas]

I will post pictures of the wiring at the drier connection, but I need my son to do this for me because I am so "lame" that I don't know how to transfer the digital photo to this site. Go figure, anyone who can mix up wires, is also the one who can't download a photo.