1999 xj heater problems

So I have posted about this a couple times but problem is still prevalent heater core has been flushed blend boor is fine and blower runs at full power it I have the air on 4 its not warm if its on 2 its like warm??? Is there a blend door obove the first? Or any advice is greatly appreciated thanks

TheBlueXJ said:

So I have posted about this a couple times but problem is still prevalent heater core has been flushed blend boor is fine and blower runs at full power it I have the air on 4 its not warm if its on 2 its like warm??? Is there a blend door obove the first? Or any advice is greatly appreciated thanks

Click to expand...

How did you determine that the Blend-Air Door is 'fine'?

hot knifed it open i only went to one? is there more than one in xjs?

TheBlueXJ said:

hot knifed it open i only went to one? is there more than one in xjs?

Click to expand...

What does 'hot knifed it open'?

More than one what - Blend-Air Door Actuator? No, there's only one.

Here's the Blend-Air Door circuit:

no the blend doors sometimes come off track which is wrong in this case the easy fix to it is hot knifing the hvac box open to put in new blend doors without removing the whole dash only problem is, is that everything works great. but the heat...

time for a new heater core. It's apparently plugged more than a flush can remove.

what i thought but both tubes are hot?? and good flow on the flush? water pump has nothing to do with it unless it goes out completely out so i was thinking about using crl but it eats aluminum so any advice on what to use or try next?>>

what does everyone think of a CLR flush?

I'm having a similar issue. 2001 XJ. No hot air but dials work on dash to change from windshield, feet, face vents, etc. Removed glove box and looked under dash to find blend mechanism. It works when I turn dash dial from got to cold and back. I see it turning the mechanism and for a moment I had warm air on red and cool air on blue. Lasted for a day then back to nothing.

I removed both heater core hoses from the water pump area and flushed both ways with a water hose. I had good flow both directions. I hooked everything back up but left "water out" hose off and it shot out hot water fine. Hooked everything back up and warm for a day but not now.

I had been noticing that all summer when running the A/C and sitting idle I could here a click in engine compartment and the engine would change idle. I figured it was the A/C compressor kicking in, but it changes about every 15-20 seconds. I thought that was a bit too often but whatever? A/C was decent but at high speeds goes hot.

Now I've noticed that this still happens when the A/C is suppose to be off and the heater is on? Why would compressor kick in for heat? Or am I hearing something completely different than A/C compressor?

Air blows everywhere the dash dial is set to. It's just room temperature (cold right now). Could this be a switch issue that's engaging the A/C when it should be activating heat? Why did I have heat for a day and then none?

Hopefully something about mine will help TheBlueXJ?

I think its called the heater control valve. Its on the passenger side up top near the firewall. It clicks and has something to do with the heat. Heat went out on a friends xj and it ended up being because the vacuum line came off the heater control valve.

I will poke around for it. There's 2 noises. One is a clicking that sounds like an old mechanical clock in the upper dash. The other is an identical sound and reaction to what an A/C compressor kicking in under the hood.

I'll post an update.

I found that my A/C compressor is kicking on and off every few seconds while the heater is on? Dial turned to the right (no snowflake) and the other dial turned tobred. A/C compressor keeps coming on and off.

Could my dial be messed up? It changes from dash to defrost to feet like it's suppose to but....