All speds out? Grab a volt meter or test light, turn controls to heat, and fan on high, is there 12 volts at the fan plug? If no, either the motor, or the switch, or the blower motor speed controller, is defective, you can test the switch and wires by the above system, if volts get to the plug, and fan doesnt operate, replace fan. If no volts at plug check at the blower motor speed controller, if it has power there, but not at blower, replace it, if no power to the speed controller, replace the switch. Auto temp control systems have blower motor speed controller, manual system has blower motor resistor. Test the same way.
Wednesday, December 30th, 2009 AT 5:42 PM
