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The Heat is On

DanDXJ

NAXJA Forum User
Location
Raleigh, NC
I have a 2001 with 4.0L ,auto and A/C. No matter what the temperature setting is it blows hot air. The fan works on all speeds, the mode selector changes from floor heat to defrost to vent as desired. The A/C clutch engages and accumulator lines get cold. However, I get nothing but hot air inside. There is no heater control valve in the heater hose under the hood. The heat selector switch appears to be electronic, not a slide switch like the older XJs. Is there a way to test the switch? I assume it is not cheap from the dealer and would like to know that it is the problem before forking over the cash.
I appreciate any help you folks can give.
 
Thanks for the reply -- I found the blend door actuator and removed it. I can manually operate the blend door with pliers and get the temperature to change. The default mode is heat so I have to restrain the door with pliers in the cold position for the A/C to work. Now I know the blend door works, the big question is, is the actuator not working or is the contol knob/switch which controls the actuator not working. Any suggestions on testing these would be helpful.

Thanks

DanDXJ
 
I have replaced the blend door actuator(motor) and the dash heater/AC control panel. The problem still exists -- blows hot air no matter what the temperature control is set to. The temperature control and the blend door actuator are both getting power. The wiring diagram shows an interface between the temperature control and the PCM but I'm not sure how this would effect my problem. Any suggestions on what to check next would be appreciated.

Thanks

DanDXJ
 
On a US left hand drive XJ the blend door is on the right hand passenger side of the floor console up on the bottom of the heater box next to the heater floor discharge. A sketch of it is in the link in one of the above posts. It is a black box about 3 inches by 3 inches and 3/4 of an inch thick . It is actually easy to locate. It is held in place with 3 screws and when removed allow the motor to slide off the blend door post. It has a three wire electrical connection on the back. You may have to fold the carpet back to allow a socket wrench to get access to the screws. If your XJ is right hand drive I would assume it is in a similar location in the left hand passenger side.

If I can help further let know. My problem still exists even with a new actuator(motor). After installing a new heater control and actuator the motor still does not work.

DanDXJ
 
Thanks for the information. I'll take a look at mine and let you know if I find anything. I already checked that there was voltage to the control switch input wires and variable voltage from the switch output wire. Thanks again - GT-UK
 
thx Dan for the info,

my rig is an 00 4.0 auto

my a/c started doin the same exact thing. everything works w/ controls but only hot comes out. lines are cold, compressor is on, all that. but oddly enough i could not located the blend door actuator (kinda like the A-hole in the fog) have been diggin on this for a couple of weeks, in AZ we are in the triple digits w/ hot air blowing or windows down. anyways, from here i can start figuring this out. i will let you guys know how this works out.
thx for all info and help!!

 
so, i got the blend door actuator off, i was able to pull the gear out of it. using the rod from the actuator i have been able to physically move the blend door from hot to cold, and cold comes out!!!

question for you guys is how to i determine if the controls are bad or the actuator is bad? any way to test either of them?

thx in advance, Cade
 
long shot, but, any known fix for this issue?

Always helpful to post year and any other pertinent info.

Also, you have drug up two posts on the same issue, best to stick with one thread at a time. :confused1
 
actually, one is on mixed heat(other thread), and this is on nothing but heat... I thought they were 2 different issues, but if not that is good news.


Jeep is a 1997 sport, 4.0 5spd... it does have a/c.


as of now...
I went out and actually "looked" right at the thing in the passenger side footwell that controls the blend door (searching here me there...)

When I adjust the cable by hand, I can contol heat, and switch to a/c... by simply moving the cable to and fro... and it definately will run the a/c.
When I set the cable by hand so it blows cold air... the dial moves to the cold position... and by turning the dial it moves the cable back to hot...
But, once turned to hot, the dial will not move the cable back to cold, the dial just spins freely...

So, how do you go about removing the "dial" and installing one that will "hold/move" the cable...


So if I can figure that out I have my "heat only" deal figured...



But, I still would like some help on why heat blows out the drivers side footwell when the AC/heat system is turned off.
 
On a US left hand drive XJ the blend door is on the right hand passenger side of the floor console up on the bottom of the heater box next to the heater floor discharge. A sketch of it is in the link in one of the above posts. It is a black box about 3 inches by 3 inches and 3/4 of an inch thick . It is actually easy to locate. It is held in place with 3 screws and when removed allow the motor to slide off the blend door post. It has a three wire electrical connection on the back. You may have to fold the carpet back to allow a socket wrench to get access to the screws. If your XJ is right hand drive I would assume it is in a similar location in the left hand passenger side.

If I can help further let know. My problem still exists even with a new actuator(motor). After installing a new heater control and actuator the motor still does not work.

DanDXJ


Dan,
the actuator and all other components may work great but the blend door may still not move.
it could be that the plastic mold at the base of the blend door has broken.
this would allow everything to appear to be operational but in fact the blend door may not be moving at all. think of it like a stripped out connection.
 
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