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Thread: AC and heater blower circuit 1998 Buick Regal 3.8

  1. #1
    Join Date
    Dec 2010

    Default AC and heater blower circuit 1998 Buick Regal 3.8

    Haynes GM manual 38010 pg 12-81 chassis electrical system and ALL DATA Diagnostics & Schematics from Auto Zone

    I have a 1998 Buick Regal, 3.8 engine, with manual AC and heat control. I have replaced both the blower motor and resistor. I am on the 3rd resistor now but still I have no low speed blower operation. It did work for about 1 year then the low speeds quit again...The high speed works but has about a 20 second to 1 min delay (periodic) before coming on. The original resistor caused the blower to engage almost immediately. Does not always come on then, sometimes I am required to turn of the ignition and then turn back on. I have done complete wiring diagnosis and trace and still have the heater control access apart for servicing.

    I have power to the control and 12v present on each tab. When I plug it into the resistor I get approx 10.5 volts on each tab except the high speed which registers 14v at the blower connector.... There are two additional wires on the resistor, connector, which I checked and traced which are as required; 1 large and 1 small orange wire.... I have been using Duralast #783 resistors and actually replaced it again in case of a faulty resistor. There is no relay present except as part of the resistor. All fuses and relays check ok.

    My understanding is that I should be getting lower voltages across the resistor (at the blower motor connector) for the low speed operation. I am puzzled and my question is: DO I purchase another brand resistor or is it possible something else is going on?

    NOTE: Recently I have experienced flashing instrument panel lights (turning off the key corrected this) and more recently the headlights began flashing off and on. I have had a problem for over 2 years: the right front turn signal bulb continues to burn out every 3-4 months. Bumpy roads have no effect on any of the symptoms above and I have not found and obvious short.

    Thank you,


    Master Mechanic, retired

  2. #2
    Join Date
    Jan 2007


    Hello rmbeach,

    Please see our reply to your post in our other forum, "Ask the Haynes experts: Questions while using a Haynes manual."

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