I had a similar problem in my W124. It turns out that my heater core was not working correctly. It was stuck open and made my heater stay on. That lead to constant heat, and NO AC. When I replaced it my AC worked, and the constand heat stopped. The broken heater core made my AC and Heat stay on together, guess which one was stronger? The heat!


Get the heater core checked out, it might be the culprit.

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1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
HID/Xenon (D2S)
Keyless Entry
Monochromatic Paint (Custom Blue)
Smoked Tails
Flat Badged (front)
Debadged (rear)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS
http://memimage.cardomain.net/member.../352975_67.jpg
http://memimage.cardomain.net/member.../748335_24.jpg

there are a ton of reasons the ac may not work. first, check if the compressor is engaging and check the sight glass. those are easy to check with your eyes. do some searches here. then check if the high pressure switch is preventing compressor from engaging (again do some searches here, involves using a jumper wire to bypass the switch and takes 10 seconds).

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car