Fan/blower switches-300e
 

Hello,

I own a 1990 300e on which the fan/blower switches have failed.
You know the ones, the high speed, auto and low speed switches . They failed one at a time. Does this mean the swithes are bad or is the blower regulator gone?

Any help is appreciated.


BR,

Richard

Fan
 

Richard;
Try pushing the defrost button,this should produce high blower speed regardless of fan selector. If you get no results you can figure that the blower or regulator have gone south.
I assume you have already checked the fuse.
MF

Check the connector where it comes thru the firewall(behind and to the right of the brake vacuum boost can). If this is corroded, it can give intermittent control voltages to the regulator and it can cause these symptoms. Make sure it's clean. Check the voltages here as well. The red wire connector should be system voltage, the yellow (with the fan on high) will be some where near 7.0-7.5 volts. The regulator is the ground source for the fan. Good luck. The fuse for the blower is in a little black box in front of the main fuse box. Pop it open and eyeball that fuse. It is a strip element and can corrode. Should have 12 volts on both sides of the fuse.