Since purchasing my 1994 XJS 2+2 I have always had a problem with the footwells on both sides being incredibly hot, no matter what the heater was set at. I looked into a number of possible causes for this problem, but until recently I had not had the time to really have a good thorough look. Long story short, the previous owner had both heater motors replaced at the dealership a number of years prior to my purchasing the car and it appears that the blue rubberized ducting on both sides was not properly secured to the outlets on the heater motors. These motors blow hot air directly onto my feet. It seems like it will be a simple enough job to secure the ducting, but getting access looks like quite a feat. Any advice on how to access the outlets on the heater motors without taking the entire dashboard apart would be greatly appreciated.

Thanks,

Lionel

 

Total heat all the time is not correct though. The ac should also be Omid and the controller blends air to make the set temperature. These blend doors, are driven by a motorm these can also stick, or if the controller has failed, or the feedback electronics. In full cold, the heater valve, which is vacuum operated, located on the engine fire wall, should turn off. These are known to stick as well.

The ducting is to connect the blowers to the internal hvac consolem but should seal nevertheless. Getting to them, requires some contortions, after removing the kick plates.

 

Seems that your hot water valve might be sticking, or the vacuum system is not working.

 

Water does the heater valve look like? Is it possible to manually manipulate it?

 

The heater is on the engine side of the firewall, in the middle. There are two hoses and a vacuum line attached to it. Don't remember if it can be moved manually.

 

Here's a pic:

Heater Valve and Hoses-4.0 Litre - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

It has a little external actuating lever so you should be able to manually operate it.

Cheers
DD

 

Thanks, I'll check that out.

 

How much play should there be. I can move the lever between an 1/8th and a 1/4 inch.

 

The valve is full on without any vacuum going to it. The lever will be at the bottom. As vacuum is applied the lever will rise. My valve was broken inside and was staying on(letting hot coolant through) all the time. The ac was having a hard time cooling like that. My heater/ac controls do not work so I just connected the vacuum line straight from the manifold to the water valve to get it to turn the hot water off. I wish the doors in this heater/ac system were accessible.

When it gets cold enough to need the heater I will disconnect the manifold line from the valve. I bought a new valve from Barrett.
RagJag

 

Thanks Rag Jag. If I unhook the vacuum line with the car running should the lever show visible movement

 

Only if the AC is turned to cool. Turning the knob on the dash to full cool should send vacuum to the valve if the AC controls are working properly. My controls aren't working at all and the valve was not getting any vacuum so I hooked the manifold vacuum tube directly to the valve.
Doing that did make the valve pull the lever to the water off position but as I stated before, the valve was broken inside and hot water continued to go to the heater core. A new valve fixed that. Something you should check by removing the valve and applying vacuum to it or just sucking on the little tube.
Cheers, RagJag

 

So I finally had some time to spend on getting the heater valve moving very freely. The results are interesting. I now, for the first time since purchasing the car, have AC coming out of the vents in the dash as well as in the footwells near the console. The bad news is That I also have hot air blowing the the footwells in the area just above the brake pedal and on the passenger side near the middle of the footwell. The ducting is still not fastened completely so I am not sure if that is contributing to the heat or not.