Jason, Blower motor speed on 1 and 2 work straight off the switch and through the resistance wire.. Then voltage for 3 and 4 comes through the circuit breaker and the 3 and 4 work off their own relay's and again feeds throght the resistance wires. So the first thing i would check is the blower motor. Hook it up to 12 volts and see if it turns easy. The if it does, see if the resistance wires are ok. Easy to come out and look. Last, what voltage do you have going to the blower motor. If you have only 10,11, volts. It won't turn briskly. Low battery or alternator voltage. John hervey << I have been reading some past posts about the internal heater/AC blowers however I did not seem to find some solid answers. It seems like my D's blower motor only works on the highest level 1, 2 and 3 do not seem to work and 4 is nothing to scream about. Has any one had any similar problems with a fix? Or maybe where to suggest to look 1st? >>