A/C Fan Motor Intermittent Failure

Discussion in 'General Motoring' started by george, Jul 21, 2003.

  1. george

    george Guest

    We have a 98 V70 with about 85K miles. Recently we have had several
    occasions when we have been driving for about an hour with the A/C on low
    that it stops cooling. We can feel cool air at the vent but the fan isn't
    blowing it around. We don't hear the fan stop, but it does start making a
    roaring sound especially if we turn it up some.

    Two weeks ago, the dealer changed the fan motor in response to this problem.
    But, the problem has continued as if nothing has changed, except that one of
    the last two times it happened, we smelled a burning odor. We have found
    that if we turn off the A/C for about 10 minutes, and restart it, that it
    then runs properly again. The car has gone back to visit the dealer again.

    Has anyone run into this problem? What was the solution?
     
    george, Jul 21, 2003
    #1
  2. george

    shaun Guest

    Do you get any flashing lights on the A/C unit? If so get them to check out
    the resistor pack - it gives the same error code as a failing fan motor.
     
    shaun, Jul 21, 2003
    #2
  3. george

    Dan Behr Guest

    I have a '96 850 with an identical problem, roaring sound and all. To diagnose
    the problem, I shut off the compressor and continued to drive. A few minutes
    later, volumes of cool air emanated from the vents.

    Conclusion:

    The evaporator was icing up and obstructing the flow of air. Knowing that, the
    question distills down to what's causing the icing to begin with.

    Does anyone have any ideas?

    BTW, the dealer tried to rope me into changing the blower motor, as well, on
    another issue, which was that the fan motor operated on high all the time, even
    when the ignition was turned off.

    Turned out, as someone else pointed out, to be the resistor. The dealer said it
    was a bad motor. (How could it be a bad motor if it was operating very well on a
    high setting?)

    I straightened it out, but it was a pain and a future cause to be wary of such
    misdiagnoses in the dealer's favor.
     
    Dan Behr, Jul 21, 2003
    #3
  4. george

    Mike F Guest

    If the evaporator is icing up, then it's too cold, probably caused by
    the low pressure switch. If you can measure your low side pressure, it
    shouldn't get below about 22 psi (with A/C running of course). If it
    does, then the low pressure switch is not cutting the compressor off as
    it should. (When the low side pressure gets down to 22 psi the switch
    should turn the compressor off until the pressure raises to approx. 40
    psi.)
     
    Mike F, Jul 22, 2003
    #4
  5. This happened on my 2000 S-40. The only advice the dealer had was to close
    the cabin air intake when the A/C is on.
     
    Marvin Margoshes, Jul 22, 2003
    #5
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