High Fan Speed Won't Work ( Re - Post)

[renok7]

I own a '93 300E 4 matic. With the ignition key on instruments the high fan setting works normally. However, when the car is running, the high fan setting won't work. My mechanic thinks that the blower motor regulator switch is defective but he isn't sure since the high fan setting works normally when the car in not running (i.e. instruments only). Before that he had replaced the ignition switch and tried a new push button control but to no avail. Any input would be greatly appreciated.

Thanks

[stevebfl]

There is a three wire connection around the brake booster. One wire is hot, one is ground and the other comes from the pushbutton controller. These are all the info and horsepower the blower gets through the regulator. The wire that is from the pushbutton unit is the control. If the control signal is the same and the blower speed is different then I would agree its the regulator.

[renok7]

Hi Steve,

Thanks for the feedback.

I'll have it checked.

Reno