Mazda Repair: Mazda MPV A/C Resistor, heater blower resistor, aluminum heat sink

Question
I think I need to replace the a/c / fan blower resistor for my Mazda MPV 1989. Do you know where it is?  

Answer
Well, I cannot distinguish from your question if you mean the cooling fans on the radiator or the heater blower resistor. But here are both and you can use which ever one works for you.

On the cooling fan assembly. Two fan assemblies use no resistor and single fan assemblies use a resistor that looks like an aluminum heat sink. I suggest checking to make sure the fans work first. I have not had any issues with the condenser cooling speed stepper before and usually the problem is traced to a poor connection at the fans and or a burnt out fan. Use a multimeter and connect it to the plug on the fan itself, then spin the fan and with the meter set on 10V DC it should register a positive or negative power signal. This will indicate if the internals are functioning as an electric motor is little more than a generator lacking an output circuit.

For the heater fan the resistor placement escapes me for at this time there was digital climate control for some models being ported over from the 929 model. As the MPV shares more with the 2600i pickup I would suggest that it would be in the same place as that. The resistor is an open element unit and is cooled by the air from the blower motor moving across it. They are usually screwed into the heater box and are the only component in the heater box other than the blower motor itself that has wires going to it. Once again, I have never had one fail on me and therefore never needed to find one to replace it. You may be able to find it by using this picture. Just remember that if it goes through a few of these it may be time for a new switch and or a new blower motor itself.  

http://www.rockauto.com/ref/SMP/SMPDetail2.html?RU262.jpg


Regards,

John