medic8377

Hey guys.
More issues that I need advice on.
ok I was having issues with the heater box. the doors were not operating properly. I was not getting the defrost, and the blender door seemed stuck, so my stupid *** took the entire dash apart and got the heater box out. all the doors are fine inside the box, but the electric motor for the blender door has a lot of play. How do i test this motor? If its no good where do I get one? Also how do I check for a vacuum leak? I have never done that before. If i could get the basics behind checking for one it would be great
1998 xj 4.0 aw4 trans a/c
Thanks for any help with this guys

Silentj

I have the exact same model. Where is this electric door motor your talking about? I just rebuilt my HVAC box and I don't remember seeing this.

CCKen

Are you sure you have a '98. The electric Blend-Air Door actuator didn't come out until 1999.

jhilley

Check with these guys


Heater Treater

medic8377

I am the second owner of the truck and there was a past repair of the heater box. maybe the last guy put a 99 box and controller in it. But the electric blender door is there.

CCKen

Here's a diagram of the '99 - '01 Blend-Air Door circuit.





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If you position yourself so you can look up to the bottom of the HVAC Unit and to the left corner in the passenger footwell you'll see the actuator.


Turn the ignition switch to RUN, and while looking at the bottom of the actuator, turn the temp control slowly from red to blue, back and forth, you should see the white intermediate drive shaft sticking out of the actuator rotate about 90 degrees each way. If it won't move, remove it from the HVAC Unit and leave the electrical connector on it then try running it again. If it still won't move see if you can get one fro Rockauto.


If it moves when removed, try moving the Blend-Air Door extension with your fingers or using pliers. You'll know if it's lammed.

CCKen

Concerning vacuum leaks, open this link and look at all the places you may find a broken/cracked/chafed vacuum tube. Some pics are of earlier XJ's.


https://www.cherokeeforum.com/g/album/3212409


The tube going to the vacuum reservoir that goes behind the battery sometimes gets broken.


To view the vacuum reservoir, lay on the ground under the front bumper right end cap, then pull down on the forward edge of the right wheel well plastic liner. Using a flashlight you can see the vacuum connection to the reservoir.

medic8377

CCKen Thank you!!!! I will update after I do some checking

medic8377

Update: I reconnected the wiring harness and the blend door actuator works just plugged in to the harness, but a new problem arose. The relay in the harness is screaming. It is making a god awful noise. Wining like crazy. I do not have any idea what this means. With the whining the blower will not spin. Is that just a relay issue? Is there another electrical issue I need to look for?

Silentj

Do you have the plug for blower reversed?

medic8377

I have no idea. I have not cut any wires as of yet and the standard plugs are still being used. Also the blower worked fine before I touched it.

Silentj

No need to cut any wires. What I meant was did you plug the connector in the wrong way. It need to be plugged in a certain way.

medic8377

oh ok everything was plugged in properly