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1998 Volvo V70 Question: Heater Fan Blower



jsc, w/o Turbo, Seattle, WA, November 05, 2009, 21:54

The heater fan stops from time to time and then comes on and/or speeds up when the brakes are applied. It will shut off completely, then spontaneously comes back on and then may speed up when the brakes are used and then slows down to normal speeds - and then will spontaneously shuts off. What is the connection with the brakes? Is there an electrical connection? Is there some physical shifting of the the fan when the brakes are applied?

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  • Answer #1

    November 06, 2009, 11:05

    Do you have automatic or manual type climate system? Are the lights for the A/C control head flashing?
    This sounds like an issue with the blower power module, it is what controls the fan speed. Most cars use a resistor pack to control the fan speed, this is done electronically. My thought is that the blower power module or the A/C control head is the problem.
    About the braking connection, these fans are electronically controlled from a blower power module, and that is controlled by the A/C control head. As the vehicle gains speed the blower fan speed is actually reduced slightly by the control module, this is to compensate for the added airflow through the vehicle as the car is moving.

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  • Medium-star Best Answer
    Visitor, September 09, 2010, 13:40

    Mine was doing same thing. The motor is so woren out that it can't start on it's own. I could spin mine by hand and it would start & run. Great detailed video on youtube on replacing it.

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    me2car, October 12, 2010, 12:08

    youtube? what should I type in couldnt find?

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