Heater?

My moms 08 jku is having heater issues. Sometimes when you go to turn the fan on nothing happens, you can turn the knob back and forth and nothing happens. Other times it works fine, any hints

Blower motor resistor could be bad. Does it work on high only? Also check the wires going to the blower motor.

rinkishjk said:

Blower motor resistor could be bad. Does it work on high only? Also check the wires going to the blower motor.

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When it works it works at all levels and when it don't work it don't work at all. And I will check out the wires. Thanks.

Ok so I posted this up a while back. Sine the original post I have replaced the blower motor and resistor, any other ideas? Any input would be much appreciated.

I guess first thing I would try is to pop off the lead going to the blower motor, then hook it to a multi meter and run the switch through its range of travel several times to see if you have any dropping out.
There are only so many things to go wrong in this system, so if the blower is known good, and all the associated components check out good then look for things like a fan impellor hitting on the inside of the housing, also check for any loose or damaged connections and any wires that may have been damaged or possibly broken inside the insulation. (that one will drive you nuts)
So if the fan switch checks out good and after several times of turning it on/ off and up/ down then start wiggling wires and connectors. If the switch checks out good then test the blower motor again.
An intermittent problem like this will about drive you nuts. Basically you need it to be in FAIL mode and then you can find the problem.
Good luck with it.

Ok thanks for the info I'll give it a shot, and hope to get it figured out.

Take the faceplate of the heater/AC knobs and check if the cable is connected.not the electric one but the metal one that moves the mix air doors