PeachParts Mercedes-Benz Forum - View Single Post - Something wrong with w126 climate control system?

tinypanzer · #2 05-12-2009, 10:17 PM

Welcome to the forum, and to the wild and woolly world of W126 climate control......

Okay, first those vent switches on the center console..... The left and right sliders are supposed to control air flow to the vents on the far left and right. Sort of counter-intuitive. One would think it would control the center vents, but no.

Anyway, if you can't get air out of the center vents, it's probably the vacuum pod that controls that flap. The whole thing is controlled by engine vacuum, and it's a goofy setup. The electronics box sends signals not only to the blower, compressor, and monovalve, but also to a vacuum operated valve bank that uses electrical solenoids that control the vacuum signals to the flap pods......The electronics box decides which flaps open, and it's done depending on the settings. For example, heat will never come out of the center vents when functioning correctly. Only the sides, floor, and defroster.

Standard repairs to get it working would probably replacing the vacuum pods, and perhaps seeing if any of the manual flaps are damaged....... You will probably need to do your monovalve diaphragm at some point, as this controls the flow of engine coolant into the heater core and when bad causes heat in the summer and none in the winter.

The gasoline smell is worrisome, I would have your fuel system inspected soon. The blower intake is in a spot which tends to suck in engine smells such as oil and fuel leaks........