Operation CHARM: Car repair manuals for everyone.

Fresh Air Fan - Changes Speed

88porsche02

Subject: Fresh Air Fan Changes Speed
Model

928 S4
Group

8
Part Identifier

8529
Number

8802
April 22, 1988



If the fresh air blower motor intermittently switches to high speed by itself, the bimetal temperature switch on the fan housing could be the cause.

The gap between the bimetal strip and the resistor coils may be insufficient.

To repair, remove the switch from the vehicle. Remove the cover and increase the gap by approximately 1 to 2 mm. Using a screwdriver, bend all four coils away from the bimetal strip (picture).

Caution: Be careful not to damage the coils. The windings within each coil must not touch each other.