Thread: A/C Help !!!!
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Old 08-04-2007, 12:55 PM
ctaylor738 ctaylor738 is offline
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Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,316
The best thing to do is look in an owner's manual - if you poke around with Google, you might find one online - and work through the various controls.

Basically, DEF should blow to the windshield and side vents with full heat and full fan. The other buttons should blow to the floor and side vents with the temp wheel up (heat), but air should come through the center vents with the temp wheel down. The compressor should get power in any function but EC. The fan should run slowly, fast or in between depending on which button you push.

It's very common for the control unit to go TU and then you get DEF as the default, which will blow hot. Also for the mono valve to stick open, which is full heat.

Lots of posts on this system.
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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