1996 XJS.

I've just got a new blower motor installed, and the air is finally coming out... Wherever it sees fit.

With the A/C on, it most of the air flows from the footwell vents. That's a bit annoying, as it's a silly place for chilled air to be released. There doesn't seem to be a normal solution.

That's not the only issue, though. Upon acceleration, the air redirects to the windshield vent all by itself.

Now, some of this may be normal for the vehicle. I don't know. I've only had their air working for a short while. Still, it would be nice not to waste the flow in the footwell when the cabin is so small to begin with.

I'd rather it not come out there. Right now, I'd just like to know if all cars perform this way. If I've got a problem, I want to sort it.

Thanks.

 

Welcome to the brilliant Jaguar Auto AC system. Mine does almost exactly the same thing. I can not get HOT air into the foot wells it blows only cold. I can not get out of the centre vents at all the air moves to the windscreen, but still blows cold in the foot well.

I cleaned all of the connectors for the AC and it did work correctly for a little while. Remove the side panels just in front of the console to gain access to the AC connectors disconnect them and clean them (I used aerosol contact cleaner and a cotton bud).

The system is a PIA and on my list of things to do is convert it to manual AC. One thing that really annoys me is; with the AC off the heater valve remains open and hot water flows through the heater matrix heating up the inside of the car especially the foot wells, so on track days I have to run the AC.

A couple of handy fault finding tips.

To check the operation of the blend flaps remove the fuses for both blower motors. Turn on the AC and move the temperature control from hot to cold and you should hear the stepper motors wurring away.

 

Ha! The heater valve? So that's why hot air comes from the vents with the A/C off? I've wondered about that for quite some time in my Land Rovers, but I didn't know enough about climate control to give it more than a passing consideration. Nobody else seemed to be able to give me an answer. It wouldn't be so bad if the air would stop coming through with the system off.

Well, there we are, then. I've asked one question, and got an answer to another one that's been nagging me for years.

Even with that little issue, I did note that the engine really warmed up with the A/C on when I wasn't moving. I'm going to make sure my coolant ratio is right, but I've got reason to believe that the supplementary electric fan up front isn't working. It doesn't fire when I engage the A/C compressor, but that might be normal. Last night, it never fired when the car met operating temperature. Today, I'll test it on hot tarmac and see what happens.

Is there a common issue here, or is this just a function that's happened to fail on my own vehicle?

Okay, on to everything else.

I'll clean those connectors and check for stepper motor operation as you suggest. Still, I'd swear it moves the airflow to the windshield under acceleration. A few seconds later, it drops back down. If it's not vacuum operated, that's rather odd.

Another question. None of my manuals seem to make this one easy to find. Why in the heck are there two temperature controls? I thought one might control the auto temperature function and the other manual, but I could be completely wrong. Right now, I've just had them both on cold.

You mention converting it to manual. I thought of doing that right after I started using it. Now, sometimes this isn't a big deal. Is this a car that can accept a manual control panel from an older model?

I'm still new to this XJS game, but I'm learning. Everything is just so odd.

 

Mine also does this and I have just installed a re-cored radiator but my fan clutch is the cause of the temp rise when stopped.

Yours is a later model than mine, however I would bet that is works the same and the later modes the auxiliary fan does not start with the AC, it is controlled purely by the temp sensor in the water pump inlet and operates when the radiator output temperature reaches a pre-determined point.


There are vacuum solenoids down there 2 on each side if memory serves me.

The reference in my ROM for the 1994 model onwards shows 1 temp control LH and 1 fan control RH it does not list 2 temp controls unless you are referring to the SLIDE control which is suppose to control hot cool air to the face.

cheers Warren

 

I've verified that the electric fan isn't working. I've just got to get in there and see why. That's obviously the overheating problem.

Relating to that... Fresh coolant was in the vehicle, no more than a month old. I figured I'd try something, since it was heating up and I could actually test something new for once. I swapped the coolant again; this time adding Water Wetter... What did I have to lose?

You won't believe this, but the vehicle stopped overheating! The stuff works. I'm shocked, but it works. Now, the engine wasn't reaching a thermal cascade, but it was heating up, and now it's not. Impressive.

I still need to fix that fan, though. I want to get it done within next week, allowing time for any parts I might need to order. All the glass is getting a thermal barrier film on Friday. It's quite light, because I'm doing the windshield as well, but it's a very effective barrier. It shouldn't be noticeable if you aren't looking for it. In a few weeks, the exhaust manifold is going to the shop for ceramic coating. I don't have time for it right now. Somewhere in between, I'll sleeve the proper parts of the A/C lines.

I'm getting that thing ice cold in this NC heat one way or another.

As for the HVAC controls, I've got three. One controls blower speed. That's on the right. On the left is another knob, which controls temperature. On the top is a slider, which also appears to control temperature.

If you would be so kind as to explain to me what those controls actually do, I'd appreciate it. Unless this is some sort of dual zone system, I can't imagine why I'd need two temperature controls.

I don't understand what you mean by hot cool air to the face, unless you refer to a dual zone system, which would seem to be pointless in a cabin of this size.

I'll check out all those stepper motors and the vacuum bits. I've also got to replace the cabin air filter foam, wherever it is, because what's left of it is blowing out the vents bit by bit. At least, that's what happens when a Land Rover filter goes. I'm assuming the open cell black foam bits are from a cabin air filter.

The car really is in great shape, it's just spent a very, very long time sitting. It's gorgeous, but it's been idle too long, and you know what that does to a car. I'm almost done chasing the faults down.

 

The electric fan is a simple 12V job, just remove the connectors from the temperature switch and put then across a 12v battery if the fan runs then the temp switch is bad. I was looking at the wiring diagram but I left my reading glasses at work (damn getting old sometimes). I would also expect there is a relay to switch the power to the fan.

The rotary control is the master temperature it controls cabin temps, the slide control lets you have hot air to the foot well and cool air to the centre vents, when it works.

Here is a cct diagram for the 1994 onwards AC

 

The fan won't give me any trouble. I'll sort it out soon enough.

I don't see why I should ever need a feature to send hot air one place and cold air another, though. That's a bit silly.

All it does is waste good airflow in the footwell that ought to be coming out of the dash vents. At least I know what it does now, though, and I can see if it's working properly.

 

Well, I swapped the fan relay out with the secondary air injection relay, and it's good.

After that, I disconnected the temperature switch and jumped the wires, noting that the fan engaged properly.

Sooooo... I suppose I'll buy a new temperature switch. That could have been a lot worse.

On a side note, I'd like to strangle the bugger that put together the service manuals on DVD. That thing is impossible to navigate and poorly scanned. All I wanted to do was find out which relay controlled the fan. I never did find the page that lists the component locations. That ought to be page one in an electrical handbook, for quick diagnosis.

In the end, it was the FAQ section in this very discussion board that made my life easier. In there, I found a diagram that was actually useful. Guess what? The component locations were in section one, right where they ought to be.