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Amelie 10-27-2011 01:46 PM

2001 WJ Heating Problem
So I'm having problems with my heat working. I just had the blower motor replaced which hadn't worked in a couple years and just replaced the thermostat and still am not getting any heat. I've been told about some kind of flapper piece that is supposed to regulate the heat or something? What could be contributing to my problems with my heating not working?


01grand 10-27-2011 02:50 PM

Re: 2001 WJ Heating Problem
You would have the basic heat, not the dual zone right? If so I believe the system is vacuum controlled, check and make sure the vacuum lines are good. From there on not sure, hopefully frango100 will see this he is the WJ hvac expert!

Amelie 10-27-2011 02:52 PM

Re: 2001 WJ Heating Problem

Originally Posted by 01grand (Post 504973)
hopefully frango100 will see this he is the WJ hvac expert!

Most definitely lol. I'll have to check on those lines, thanks for the input.

I'm thinking it might be this

Frango100 10-27-2011 10:19 PM

Re: 2001 WJ Heating Problem
Thanks for the credits, but not really an expert, but i love troubleshooting and solving a problem.
Eventhough there are vacuum controlled actuators in the manual system ( recirculation door and mode door), the single blend door actuator (your flapper piece) is not one of them. This actuator is an electric motor which you can find behind the glove box. Have a look at its fuse, its fuse 20 (10A) on the junction block when iīm not wrong.
Before you start opening the glove box, i would check the heater core hoses in the engine bay to feel if they are hot (after the engine had run for a while ofcourse:D,). There could be a resitricted or obstructed coolant flow to the heater core. When both lines are hot, there most probably is (some) flow. Didnīt hear a lot of problems with a mechanically breaking blend door on the manual system, so most probably your problem is the actuator or temperature selector. Check as well if the wires are properly connected to the heat selector knob (behind the A/C panel).

Amelie 10-28-2011 10:50 PM

Re: 2001 WJ Heating Problem
Thanks Frank, I never thought about checking the fuse to see if it might be blown out. I also read on WJ Jeeps that in 2004 they redesigned the blend doors, I wonder if they could work on 99-2003 Jeeps.

You said Fuse 20, This sound right?

F20 10 Amp Red Ignition Run / Heated seats / A/C Heater control / Flasher - Left and Right turn signal switch sense

Frango100 10-29-2011 01:36 AM

Re: 2001 WJ Heating Problem
Fuse 20 is indeed feeding the blend door actuator via the ignition switch. But the combination flasher is also using this same fuse, so if the turn signals and hazards still work, your fuse should be ok.
Just to be sure, your blower motor is blowing cold air, isnīt it? Heard of problems before that the blower was running, but in the wrong direction, and no or almost no air was coming out of the vents.
If ok, i would remove the blend door actuator and see if its moving when selecting different temperatures.

Amelie 10-29-2011 01:35 PM

Re: 2001 WJ Heating Problem
Turn signals are still working fine. The blower motor in the Jeep had not worked for a couple years and we just got it fixed a week or so ago. Up until now I don't recall any problems in the past. Yes it is blowing cold air, So the most obvious guess would be the blend door actuator like you said. We just had the thermostat and blower motor replaced so I'm thinking that's the last option.

Frango100 10-29-2011 04:33 PM

Re: 2001 WJ Heating Problem
Did you feel the heater hoses if both are hot just after switching off the engine? It still could be your heater core as well. But check the actuator and also feel if the blend door moves freely.

mtp78 10-30-2011 03:04 PM

Re: 2001 WJ Heating Problem
While the vehicle is running and at proper operating temp. You can feel both hoses on the heater core. If both are very hot the problem is in the heater box (blend door\actuator or electrical issue)

If one of the hoses is cooler than the other heater hose you might have a partially clogged core. You can try to remove both heater hoses and try to manually flush the core. A garden hose with a pressure nozzle can help to un-clogg the core. Do not use the full force of the hose . Just gently pulse the nozzle till you see good flow coming out the other tube. You can blow the core if you use the wide open force of the hose. So be careful.

Another issue to look at is to make sure your water pump is putting out proper flow( sometime the vane behind the pump rots out) after removing both heater hoses from core have someone start the vehicle and notice the flow from one of the inlet heater hoses. You should have strong flow once the vehicle is started. You should do this step first if you notice different temps between both heater hoses before the flushing I listed above.

Make sure you let the vehicle cool before you remove the heater hoses! So you don't burn yourself.

Amelie 10-30-2011 06:45 PM

Re: 2001 WJ Heating Problem
@Frango100: Nope not yet, I still need to do that.

@mtp78: Thanks for all the info, I'll try all those suggestions hear in he next few days

JeepMe 10-31-2011 06:38 PM

Re: 2001 WJ Heating Problem

Originally Posted by Reichminister Goebbels (Post 506051)
So the most obvious guess would be the blend door actuator like you said.

You can see if the actuator is working or not (I was looking at this when my heat wasn't working right). First you have to find it under the glove box. In the center of the actuator is a metal shaft with a notch in it. As you turn the temp control knob, you should see that shaft rotate. If I remember correctly, it should rotate about 270 degrees.

If it's turning, I would say you most likely don't need a new actuator. If it doesn't turn, you need to look further into the issue (bad actuator or bad electrical to actuator).

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