View Full Version : AC and heater blower circuit 1998 Buick Regal 3.8

08-17-2012, 09:02 PM
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

08-23-2012, 07:30 PM
Hello rmbeach,

Unfortunately, advanced diagnostics are not covered in our manual #38010. The other resource that you mentioned (ALLDATA) is reflective of factory service information and should contain just about everything the manufacturer has on the circuit. It sounds like your electrical problems may include other circuits. The benefit of Alldata is that you have access to all wiring diagrams for your vehicle.