So here’s another one for you wizards. This time I checked post history and couldn’t find anything so maybe this will help someone else as well! I’m having a heat issue, only cold air comes out. Hoses going too and coming from the heater core are hot so that’s good, the heater valve seems to be working as well! My last thought is that the blender door is stuck, my question is how difficult and expensive this is to fix, if it could be something else I’m missing that would help too. Thanks!

 

Blend door stuck? Or not being commanded to move?

The system is designed to refrigerate all incoming air first and then heat it as needed.

The heater valve is open in all modes except maximum cooling mode.

Slowly turn the temp control knob thru its full range. Do you hear a faint whirring? If so, good, that means the servo is doing something.

If full cold is selected does the airflow switch to the center dashboard outlet? If full heat is selected does the airflow switch almost entirely to the foot well outlets? If so, good. It means the system understands requests and is trying to comply.

I am assuming you have a Series II or III XJ6/12

Cheers
DD

 

the Series 3 XJ-6 UP TO 1987 does not have "blend doors". All Vents are opened via vacuum valves. Check the Resistor if you have a Series 3 XJ.

 

Sure they do ! Except Jaguar calls them 'flaps".

Incoming air is refrigerated and then heated as needed by directing it through the heater core. This is accomplished by the 'flaps'

Cheers
DD

 

a "blend door" is fitted and hinged vertically like a house door inside a climate box. It is usually taller than wider.

a flap can be hinged on one end also, but opens and closes up or down, or it can be hinged at the center pivoting open or closed.

My 1997 Ford has "blend doors", Vertical doors that open or close depending on the selected mode, my 1984 XJ-6 has horrizontal flaps.

I guess it can be an issue in which these "doors" can be called by either name but I make the distinction because the XJ-6 does not have VERTICAL Opening doors, or VERTICAL Opening flaps for that matter. All the flaps in the XJ-6 are mounted horizontally whether the ones at the Dash/Windshield, or the Center Dash Flap, or the two in the blower cases.

 

Ok, Jose. You win

Cheers
DD

 

yesssss! Thank you Doug for admitting defeat! haha!

 

Flaps, doors, or whatever, in the passenger footwell remove the two screws that hold the little footwell heater grill and then you can wiggle out the cheek panel (The panel by the passenger left knee). Now do Doug's tests. You will be able to hear the servo better and you will be able to see the rods pushing the flaps/doors. There are drawings of the rod linkages and when I did the above I noticed a little spring was missing. I replaced that, judiciously sprayed a little silicone lubricant on the mechanism and gently wiggled the rods and voila problem solved.