Good afternoon, - JAG XJS 1994 V12 (Assume Delanair MKIV)
After refurbishing my AC system (New AC Matrix inside cabin) and new Heater matrix (Together with Heater Valve) - i'm not getting hot air inside the cabin.

After small troubleshooting i can see that after engine gets up to normal temperature and with Defrost ON (And max temp.) my Heater Valve is not getting any vacuum (Thus not opening/closing) and not letting coolant into Heater Matrix.
Could this be a problem related to AC controls?
I must admit that i might have incorrectly (Could not find el. diagram) connected Temperature change knob (It has 3 wires connected to it). - can this be related to that? - Or maybe there is no order of connecting these?

Coolant temp sensor on one of the Heater Matrix rails is working - checked - no open circuits.

Vacuum lines seemed to be fine around AC/Heater Box.
Previously with non working AC it was most of the time hot air.(most probably coming because of engine heat);

Happy Problem - waaaay too cold inside the car

 

The valve is open by default. No vacuum = open valve. Vacuum is used to close the valve

Cheers
DD

 

My bet is that the system isn't bled properly, and there is air in the heater matrix. I also had a heater valve that had foreign matter stuck in the valve, blocking coolant flow. Feel the inlet and outlet lines going to the heater core. Engine warm, they should both be hot.
Aa was stated above, the heater valve is normally open without vacuum. It only closes when cooling is set near max, and vacuum is sent to it.

 

There is a vacuum junction box (not sure of the correct name) by the heater core. You might have disconnected one of the lines.

 

I've checked this junction box - everything seems to be connected.
Maybe Jal is right and bleeding was done incorrectly. - though car is running about right - not stable on N but not overheeting as well.

Maybe someone knows how to correctly plug electrical cables to TEMP knob? There are 3 separate wires with 3 different connections - maybe incorrect connection may cause incorrect temp readings for AC?

 

[QUOTE=yoopas;2523381]I've checked this junction box - everything seems to be connected.

But is the vacuum manifold functioning?

 

[QUOTE=equiprx;2523500]Vacuum is only needed at the heater valve if he DOESN'T want heat. He hasn't said if he gets vacuum at the valve with the temp set to full cold. If the valve is open and both the intake and return hoses from the heater core are not hot, he has air in the system.
I'd pull the valve, and make sure it's open with no vacuum applied. Then rebleed the system using the instructions in the stickies at the top of this forum. Do it with the nose of the car jacked up, or on an upward slope.