View Single Post
  #5  
Old 05-29-2005, 09:39 PM
psfred psfred is offline
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Check the serpentine belt -- on the M103/104, if the compressor speed drops below engine rpm, the Klima will drop the AC, and on the W140, this may also drop the fan.

The speed control for the fan isn't a resistor, it's a switching unit that gets an analog (0-6V, I think) signal from the ACC pushbutton unit and uses that to determine the duty cycle of the swtiching transistor on the ground side of the fan motor. You need to check that the fan has full voltage (check the fuse for condition, it's an aluminum strip in a small box, I think, outside the fusebox) and that you have a signal on the control wire to the speed control box (yellow? Some one chime in here, I'm not sure!).

However, that particular climate control is vastly more complicated than the ones in the W124 chassis, and is usually non-repairable......

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Reply With Quote