Hi Forum. I'm having intermittent problems with HVAC blower on my '04. It will sometimes only operate at full output. Per service manual I checked the resistance between resistor block terminals and measured sane values. On a couple of occasions when the blower motor isn't working at less than full output, I've been able to start it by giggling the resistor block. At the moment it is working so I cannot measure voltage drop across terminals to determine if wiring harness going into resistor block or block itself. But I did find the resistor block to look odd ( see attached ) where the terminals enter the block. Perhaps from water or overheating ? Anybody seen this before ?

Sven

 

Replace the resistor the oxidation is a dead give away

 

The resistor packs have been known to fail on vehicles over the years. You got oxidation at the connector which causes resistant that generates heat and over time will cause problems and or go out only allowing the fan to run at certain speed. At high speed its direct to the blower motor and you are getting the full voltage (12volts).


47

 

Thanks guys. There is evidence of moisture on the connector and resistor block, a couple of the terminals in connector housing are quite oxidized. Perhaps this is from condensation dripping on block from heater A/C case into which block mounts. I'll try to crimp new blade terminals before installing new one. Those replacing their resistor blocks should have a look at this. For those interested, Chrysler part #68004539AA for my truck which can be had for about $30-40 on the Internet as opposed to $55-65 from auto parts and dealerships. I'm buying the STANDARD MOTOR PRODUCTS Part # RU109 which is supposedly compatible for $40 from Rock Auto.

Sven

 

Have an 05 just started only working on high. Where is this here part located??

 

by the blower motor, most of the time you can buff the contacts and blades and use bulb or electrical grease on them. you should use it on a new one also.

 

I'll give that a try. Thank-You

 

Some relevant follow-up. Last year I replaced my batteries and the lugs/terminals of battery cables including the 6AWG wire going Integrated Power Module (IPM) and eventually blower motor. All of my blower motor issues went away so it would seem that I was dealing with added resistance in original terminal or connection at battery.