HVAC Fan not working

Cottontail

Three-De Off-Road
NAXJA Member
The new to me XJ I just picked up (2000 model) doesn't blow the HVAC at any speed or on any setting. I put in a new blower motor resistor, just to rule that out. I was pretty sure that it wasn't that, as research told me that a bad resistor would still blow on #4. I did pull the knob plate off the dash and all the vacuum lines look fine to the center indicator knob, and there are no "burnt" wires leading to any of the other knob plugs (particularly the blower setting knob.

Before I start tearing things apart - it has to be either the switch or the blower motor itself - what tests can I do, and how would I do it to see if I can isolate the issue? I really don't understand wiring and the electrical part of repair.

I saw one post on the internet that said it could be a vacuum leak at the ball behind the pax side bumper, but I was under the impression that was a cruise control vacuum canister.
 

Saudade

NAXJA Member
NAXJA Member
It is but it also supplies the vacuum operated vents. So if blowing only out the defrost would indicate a vac leak.

First, check the fuse. The you'll need a volt meter (or noid light) to verify power at each side of the fuse, then start swimming downstream. Could be a grounf as well.

Did you test the fan before installing it?
 

MichXJdad

New member
Check the fuse, if it's good unplug your blower motor in the engine compartment and check voltage on the harness side of the plug. Blower motor is a Pita but doable if it's bad. Careful not to over tighten the 3 hex screws holding it in when re-installing, mine easily stripped installing my new blower and had to re-enforce with jb-weld. Good luck
 

Rob Mayercik

NAXJA Member #920
NAXJA Member
You can also try jumping straight from the battery to the fan connector (it's only 2 wires) to check the fan motor directly.
 

EvaB99XJ

NAXJA Member
NAXJA Member
If you find that it is a dead blower motor you can get to it by removing the bracket that holds the a/c accumulator in place and rotating it up out of the way - that way, you don’t have to evacuate the a/c system.

The only other thing you might need to do is to slightly bend the sheet metal out a bit at the 5 o’clock position to allow the new motor to go back in.
 

Cottontail

Three-De Off-Road
NAXJA Member
Well, here is where I am at with this. I checked the fuses and the relay and all them are good.

In researching, I read that when I change the fan speed, I should hear/feel the relay switch activate. That is not happening. I tested the relay with a multimeter and also put a known good relay into that spot as a second test. I felt/heard nothing on either relay when I moved the dash knobs.

I did confirm that the vacuum is good as the actuator rod did it's thing as I moved the center knob from position to position.

So, if I am correct, that tells me that the relay isn't getting power and there is an issue between the relay and the fan switch on the center stack.
 

OPXJ2010

NAXJA Member
NAXJA Member
I had this issue. I checked fuses, Vacum leaks and replaced the resistor under the dash. still nothing. took the hvac controler out of the dash to find one of the plugs had became disconnected. plugged it back and the fan started to work again.
 

Cottontail

Three-De Off-Road
NAXJA Member
Tried a different switch panel this afternoon. Still nothing.
I had this issue. I checked fuses, Vacum leaks and replaced the resistor under the dash. still nothing. took the hvac controler out of the dash to find one of the plugs had became disconnected. plugged it back and the fan started to work again.
I thought about that also - but I tried a completely different controller, and neither of them worked.
 
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