So I'm out of ideas on this one. Currently my blower motor appears to not be getting power. I have a 2002 Grand Cherokee Limited with Dual Zone temperature control. This problem coincided with the blend doors failing for the 2nd time. I've replaced the blend doors but the blower motor is currently without power. I replaced the blower motor resistor last winter and bought another new one this past week and tried it out without success. I've checked all the fuses and no luck. I took the blower out and tested it on a battery and it runs perfectly fine. I really don't know what else to do.

Any ideas or suggestions? I need help!

 

Welcome to CF!

The dual zone heater has a computer module inside it that controls everything, even the blower. You don't have a blower resistor, instead there's a module that goes there. The blower speed is controlled by the central unit and is variable. There is a way to get trouble codes out of the heater, but IDK how. You'll have to do the research on that. Check on wjjeeps.com

 

Check the connector where it plugs into the blower motor resistor unit - these are known to melt and cause a bad connection.

 

Mike, the dual zone control doesn't have a resistor. That's replaced by an electronic module.

 

I did get codes from the heater but they are historic codes that go back to the blend doors that were recently replaced. It seems like there is some issue with the blower motor where it isn't getting power.

 

I understand what you're saying, but that power is variable and is supplied by the unit itself, not by a blower switch. Actually, I believe the supply current comes from a fuse and the blower module decides how much voltage gets thru to the motor. The blower module is controlled by the console unit.

 

I got the fault codes out of the module.

51 = AI (Recirc) door travel range too small
52 = AI (Recirc) door travel range too large
53 = Left temperature door travel too small
56 = Right temperature door travel too large

This seems like it's the blend door fault codes. Could the blend door actuator be out?

 

Now you're asking me how a computer thinks! I believe that's beyond my knowledge. This stuff is the reason I bought a Laredo!

Sorry, had to unload.

 

Those could be historical fault codes - have you tried clearing them ?
Have a read of this : http://www.wjjeeps.com/climate.htm and this : http://www.jgcparts.com/JGCParts_AZC_Recalibration.html