[W126 Coupe] Heater / AC Fan

[Mister McGoo]

Henry;
 
The fan appears to be running at a very low speed, even when the "defrost" button is activated?   There are two fuses, one in the fuse box with all the rest of the normal fuses.  Check the list under the fusebox lid.  (This one is unlikely as that fuse is for other functions also, if I remember correctly)  There is another fuse in a separate little black box outside the fusebox.  I'm not 100% sure where on your car but look for a black hinged box 3/4 inch wide and less than 2 iches long.  It could be in front of the brake booster.  (On older cars it is on the fender in the engine compartment itself in front of the fuse box).  Inside is the 30 amp blower motor strip fuse.  It is held down by two screws.  Check those fuses first.
 
If the motor is still running, even a tiny bit, the more likely problem is the blower motor resistor regulator malfunctioning.  Has this been intermittent?   This regulator controls the fan speed.  MB likes to hide this gizmo in an inaccessable place.  It is a 4" triangular metal thing that sometimes is referred to as the "bed of nails".  On older models it is under the power brake/master cyl assembly, on the W124's I believe it is under the heater fan itself.    

-Bellamy 


From: henryviv at oigp.net
To: mbcoupes at mbcoupes.com
Date: Sun, 27 Feb 2011 12:09:03 -0800
Subject: [W126 Coupe] Heater / AC Fan



The blower fan for my 1991 560 SEC does not function. If I press the AUTO of High, or Low button, the fan stays the same (very low perceptible air flow). I don’t know how to determine which of the fuses or relays to check or replace. Any suggestions?
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