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Dave
Dave, Jeep Master Tech
Category: Jeep
Satisfied Customers: 1158
Experience:  Chrysler Triple Master, ASE master Tech AA degree in Auto.
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97 jeep cherokee: heater/ac..ac fan..heater controls..ie compressor

Customer Question

97 jeep cherokee heater/ac fan won't work while other heater controls work ie compressor goes on when control activated
Submitted: 7 years ago.
Category: Jeep
Expert:  Dave replied 7 years ago.

Hi, if i understand you correctly you are saying that the heater control fuctions and A/C control functions work fine but the blower motor never comes on.

 

Is this correct?

 

Dave

Customer: replied 7 years ago.
yes, correct
Expert:  Dave replied 7 years ago.

Hi, ok if the blower motor doesn't work on any speed then the problem is in either the control head, resistor module, wiring or the blower motor itself.

 

I see you replaced a switch, was that the control head assembly or the blower motor resistor module?

 

What we need to know is if the blower motor is any good or not. The way to do this is to hook it directly up to the battery. Run a wire from the positive terminal on the blower motor then take a piece of wire and touch it from the neg pin of the blower motor to ground and see if the fan turns on. If it doesn't then the blower motor is no good.

 

The next tests you will need a test light for. You want to test and make sure you have voltage in the connector for the blower motor. You could also do this test before testing the blower motor. What you need to do is to disconnect the connector from the blower motor and put one end of the test light on one of the connector terminals and the other end of the test light on the other terminal. Now turn the A/C selector switch on and turn the blower motor on low, does the test light light? Do this for all blower motor settings. If the test light never lights then take the test light and hook one end of it to a good ground and probe the blower motor connector terminals, key on, a/c selected and test for voltage on all blower motor settings check both terminals of the connector and note if you have voltage on any of the settings.

 

If you have voltage on all setting then the ground signal is bad. First place to look is in the wiring connectors right there on the heater case, look for any signs of corrosion melting etc.

 

Now if you get poser and ground on only high then the resistor module would be bad.

 

Dave

Customer: replied 7 years ago.
i removed glove box door & see a relay #56006709-50732 lower number stamped 2056a1 is this for fan motor? if so i have others w same top #s but differernt stamped #s would these be the same relay
Expert:  Dave replied 7 years ago.

Hi, most relays are the same part number. Why are we looking at the relays for a blower motor problem?

 

Dave

Expert:  Dave replied 7 years ago.

Hi, is there anything else i can do for you? If not please choose to accept so i can get paid.

 

Thanks

Dave