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HELP! A/C problems in Arizona

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cdh, Jul 3, 2002.

  1. cdh

    cdh Registered Member

    May 6, 2002
    Likes Received:
    Gilbert, Arizona
    I have an 89 Blazer and I burned up my second blower motor switch. I cannot adjust the blower speed at all. I think that the switch relays are bad and they are buring up the switch on the dash. Does this sound right? If the relays are the problem, where are they? I think that there is one in the engine compartment right by the blower motor, but I have no idea where the second relay is. The high for today is 113 degrees, so as you can see I need to get this fixed fast. Thanks for your help!!!
  2. 95 Silverado

    95 Silverado 1/2 ton status

    Nov 9, 2001
    Likes Received:
    Central PA
    I would think a failing blower motor would be more likely to cause the switch problems. you have four components to deal with: switch, motor, relay, blower resistor
    switch: when this goes bad it quits working, motor won't run
    motor: as this gets old it pulls more current, sometimes squeaks, and puts more load on the other components causing them to fail
    relay: this bypasses the fan switch on high speed and powers the motor directly, you can lose hi-speed or the low and medium speed or all of them but it usually won't burn up the switch
    resistor: this is in series with the motor on low and medium speeds to reduce the voltage and slow it down(on high it gets full voltage) if this goes bad you lose low and med. speeds but will still work on high
    the a/c system probably pulls some current through the switch also but I would suspect the motor as the troublemaker

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