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Carguyjosh, ASE Certified Technician
Category: Jeep
Satisfied Customers: 2172
Experience:  18+ years repairing Jeeps
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2002 Jeep Grand Cherokee Limited.Heater not working. Checked

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2002 Jeep Grand Cherokee Limited.Heater not working. Checked the inlet and outlet hoses and they are both hot.Checked all the fuses in the power distribution box except the big ones that require a testing device.All the doors work as does the blower. The car has dual controls for heat and air,could the controls be bad.

Good evening.

Has the loss of heat be a slow decline or all of the sudden?


If you put your ear to a heater vent and switch the controls from cold to hot, do you hear a change in the sound of the air flow?


Please let me know...Thanks, Josh

Customer: replied 5 years ago.
Heat loss was all of the sudden.Have not tried to switch from cold to hot and listening, but the a/c works fine.


It sounds as though you are having a problem in the heater box assembly.

There are countless service bulletins about air doors breaking and blend air door motors failing.

Since the problem has occurred all at once, on both sides, I am leaning towards a broken air door.


I can tell you that the last heater box that I removed I ended up replacing two air doors and both the passenger's and driver's blend air door motors.


I order to resolve your problem it sounds as though the heater box will need to be removed and all of the doors examined.

Even if only one door is found broken, have the passenger's side blend air door motor replaced.

The passenger's door motor is a very common failure and the entire box must be removed to replace it. Rather than having to pay the labor twice, have them replace the motor..


You can expect that this will tie your Jeep up for about 2 days. 1/2 day to pull it apart and another 1 1/2 days to wait for the needed parts and reassemble everything.


Please ask me any questions that you may have,....Thanks, Josh

Customer: replied 5 years ago.

I can hear all the doors opening and closing from floor to defrost.

I failed to mention that although te a/c works fine I can not adjust the temp.

Hopes this helps.

The door that controls the switching from floor to vent and then to the windshield is the mode door.

Its not actually the mode door that is failing. It is the blend air doors as well as the door that switches in between the heater core and the air conditioning evaporator core. The shafts are breaking free inside of the plastic doors and the doors just get stuck in that position.


That is why the A/C works fine but you can't control the temperature....


Thanks, Josh

Carguyjosh, ASE Certified Technician
Category: Jeep
Satisfied Customers: 2172
Experience: 18+ years repairing Jeeps
Carguyjosh and 3 other Jeep Specialists are ready to help you
Customer: replied 5 years ago.

Is there anything I can do to free these doors up or maybe a vacum leak problem or are they just shot.

Thanks for your help. Great job!

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