'08 Liberty sport (manual temperature and fan controls)
The blower motor in our Liberty started making some unusual noises early last week. I didn't look into it immediately as I'm in the middle of a FMS replacement on my WJ, but within a few days it stopped working on all but the highest fan setting.
Turns out the bearing went bad in the fan, and after some continued use it burned out the resistor. This is a very easy replacement, so if you're a newbie this would be a good place to get your feet wet.
So if your fan is exhibiting odd behavior it's because of one of two things:
1. the blower motor resistor is damaged (Mopar #68003998AA, $12.64 on weRmopar.com)
2. the blower motor is damaged (mopar #68003996AA, $75.00 on weRmopar.com)
If the fan runs on all speeds, but sounds funny (like ours did) it's probably the motor. If it only runs on high speed but sounds fine it's probably the resistor.
To get to the motor, remove the padded cover in the passenger footwell. There are two plastic screw type fasteners at the forward edge. Also remove the plastic kickpanel/trim piece. There are no fasteners for the kickpanel, just pull gently and it you can dislodge the slot & tab retainers:
Here's the blower motor:
Locate the three screws holding the motor into the rest of the HVAC system. Disconnect the electrical connector from the motor and use a T20 torx driver to remove the three screws. The motor drops right out and you're ready to swap in the new one. Here's the new and old motor sitting next to each other:
The rust on some of the internals make me wonder if there was some excessive moisture in there that contributed to the bearing failure at 50,000 miles.
As for the resistor, you access that from behind the glove box. Just open the glove box and push the little retaining arms inward to allow it to open all the way. The resistor is held in by two screws and has a gray electrical connector plugged into it. In this shot I've already removed the connector and screws:
There is a metal tab soldered to the rest of the resistor. If the resistor has failed, that metal tab pops up and breaks continuity. That's an intended failure mode like a fusible link. In the following pic I had re-soldered the tab for troubleshooting purposes: