Iroczepp

My fiance's '03 WJ has issues, and I am laid off at the moment and am keeping busy while she drives my rig.
current issue is the a/c air will not blow at all. Not on any setting. Blower motor?

Additional info: (The battery may have been disconnected incorrectly) just replaced radiator fan relay to fix fan- success
replaced all dash light as most were not working -hooray
flasher relay on order as turn signals not working but hazards are.
Replaced one cracked hose connection on driver side vacuum line.

I'm not trying to throw parts at this thing that are unnecessary so I'm hoping to test parts to replace them. Please give suggestions to narrow this a/c air issue.
Thanks

Noah911

You could begin with checking the #1 slot blower motor fuse in the engine compartment power distribution center (PDC). Look at it to make sure the fuse is not blown, and then use a multimeter or a test light to verify if there is a normal continuity when probing the two little metal testing points on the top side of the fuse.

Do you have the Automatic Zone Control (AZC), or do you have the manual temperature control for heater and air conditioning?

The problem is most common on the WJ Grand Cherokee with the AZC. The AZC equipped WJ has a Blower Motor Controller Module. The connector on the module overheats, and the result is intermittent or no operation of the blower motor. The AZC Control Module is located underneath of the dash on the passenger side inboard footwell area. If you look at it you may find melted wires. If you wiggle the wires around with the blower motor turned on the motor may begin to run for you.

For the manual temperature control equipped WJ there is a Blower Motor Resister (instead of the Controller Module) in the same location. When the resister goes bad it usually gets stuck on just one speed vs having an all out blower motor function failure.

If the Controller Module (or resister for manual equipped models) has gone bad. You should check the amperage of the blower motor after it is fixed to make sure it is not pulling more than 13-17 AMPS. Pulling too many AMPS could have been the cause for ruin of the controller or the resister.

Pull out the blower motor and check to see if it spins freely and it is not jammed up with debris.

Iroczepp

So the fuze is good, and the fan will not work on any speed, so I just need to find the blower to test? Is that under the passenger dash?

Pulled blower, hooked up to a small 12v battery, blowing fine. I cleaned it too, needles and crap stuck in the back.

So is there a relay or common fail point I can check?

Noah911

Do you have the AZC Automatic Zone Control, or the Manual Temperature Control option?

There is a Controller Module for the AZC. And a resistor for the manual model. They both are located in the same spot as one another, and inboard of the blower motor

Iroczepp

Manual, and no speeds work, so that would rule that out?

Noah911

IDK?

I did read you can use a multimeter on a manual resistor piece, and measure it for continuity at all of the corresponding climate control switch settings, as one way to test it.. You could probably test it for power?

Iroczepp

The resistor works, I tested it.
the motor works, I tested it.
The control module actuates the doors, the compressor kicks on. But no lights when turning on A/c.
side note, also can't get turn signals working, replaced flasher relay and that did not solve it.
Is there any other component I can check or is it most likely a wiring issue?

Iroczepp

Update: found #20 fuse under driver side blown. Replaced and immediately blew again.

If the motor is drawing too many amps would it blow the fuse immediately? What would cause an immediate fuse failure?

Noah911

The #20 junction block fuse is an ignition/run fuse. For a 2003 WJ it gets power on when you turn the ignition key into the RUN position to power its circuits.

It controls the heater, a/c, heated seats if equipped, and ties into the left and right turn signals.

You can isolate it by pulling the switches, fuses, or power at each one of those circuits individually and turning the key to run to see if it blows the fuse each time for all of them. Replace the fuses in-between.

(copied and pasted)
disconnect the flasher molex connector from the steering column, replace the fuse and turn the key on. If the fuse doesn't blow then the fault is in the flasher unit, if it does its on the key side. Use a test light to probe any short to ground problems, follow the wiring diagram and do a visual inspection make sure all grounds to the circuit you are testing are solid.


This guy here had the same problem, and it was traced through the wires to a bad spot at the transmission.