Jim Grant's Tech Tips
'00 Dodge Grand Caravan, Blower Motor Fun
I own a "00 Dodge Grand Caravan and the blower would only work on two speeds. I replaced the blower motor resistor and the wires on the resistor were broke. With the new resistor I had 3 speeds but my blower motor would not shut off when the van was turned off. I only have high blower speed now.
The blower motor in your vehicle receives power from the blower motor relay. When the ignition is turned off the relay is deactivated preventing electrical power going to the blower motor. If you turn the ignition switch off and the blower motor continues to operate it is likely that the blower motor relay is defective. As for your speed problem that sounds interesting. As mentioned earlier power is supplied to the blow motor via a relay. The blower motor's speed is controlled on the ground side by the blower motor speed switch in the A/C Heater Control Module. The most common cause for loss of blower speeds is the blower motor's resistor block. The blower motor resistor block provides for all of the different blower speeds other than high. High by-passes the resistor block, goes through the switch to ground, allowing the blower motor to run as fast as it can with all the electricity it needs. If the lower speeds are missing go back to the resistor block, you may have mixed up the wires when they were repaired, maybe a bad connection or a failed resistor block. If you find that the resistor block has failed again check your work very closely on the wiring repair. Last but not the least expensive is the part that holds the blower motor switch- the A/C Heater Control Module. "Module" is another word for computer and the blower switch activates different drivers for the different blower speeds. Yeah, drivers are computer type things that can be damaged or just go bad. If all of your repairs check out and it's looking like the blower switch is the cause you'll get to replace the A/C Heater Control Module. When you buy the A/C Heater Control Module you get the blower switch free (something like that) it all comes as one unit. Hopefully there's just a relay and a mix-up on the resistor wires and/or a failed resistor. A damaged A/C Heater Control Module will put a good dent in the charge card.