Hello all;

I currently own a 1994 Jaguar XJ6 Sovereign Series and was advised the XJ40 Forum was the one to seek help?

Essentially my climate control fan wont spin, when the system is turned on the heaters heat up, the indicator lights on the buttons all light up, and when stationary or moving you can feel heat coming through the vents and dash as moving air casually pushes it through and the vehicle itself warms up. Big problem comes from the cold when windshield needs defrosting or vehicle warm up.

Looking for advice on where to begin looking to find the problem?

I've started with only the fuses and all seems to be in good order.

 

Late model XJ40's (like mine and a number of others!) have a problem with cold/cracked solder joints in the fuseboxes. The main joint to crack is the center joint which powers the blower fans.

You can check to see if you have power at the fan by backprobing the plug at the fan (I think it's the brown wire) - there should be power (12v) on that wire even with the ignition off. If that wire is dead it is almost certainly a problem with the solder joint in the fusebox. Re-flowing the joints will fix the problem. Had to do both of mine - went almost all winter without fans - not fun.

 

Perfect, I'll have to get a tester and start there, thanks for starting point.

 

I'm not so sure it's the fuse panel, as each blower gets power from a different fuse in a different fuse panel, so it's less likely to happen to both at the same time.

I would start by looking at the fan speed switch.

Cheers,

Allan

 

Yes, true, both wouldn't go at the same time - however, on my car one side had never worked (didn't know that when I bought it) and the fan(s) only ran on high. After about a month of ownership, the fans quit altogether.
Using the same logic (that both wouldn't quit at the same time), I replaced the microswitch in the control unit but symptoms persisted. Apparently the microwitch problem is more of an issue with early XJ40 control panels and not so much with the later ones.
From a tip from another 94MY owner on the forum, I re-soldered the driver's side fusebox and my fan came to life, again, only on high, so I decided to re-build the speed control circuit (transistors etc) in the driver's side fan - the passenger side required removal of the airbag so I thought I'd do the easiest one first.

While I was waiting for the parts to arrive, I removed the passenger side fusebox to have a look, and to my surprise the very same solder joint had cracked in that box too. I re-did the solder joint and found that I now had low/med/high airflow, albeit only from the passenger side, the driver's side still only blew on high. About a week later I removed the driver's side blower and rebuilt the transistor speed control and replaced the relays.

That was it. Fixed!

 

Interesting. My 91 blows only out of the front demister, and only on full fan, nothing on anything less. Cant seem to get it to blow out of the face vents...

 

Im having trouble locating the wires for the fan, could you give me a little direction to help identify the correct wire. (Location wise).

 

After you remove the driver's side kick panel, look for the brown cylindrical plug. Take it apart and check for power on the brown wire. There should be 12v on that wire even with ignition off.

 

How can I locate the switch you are reffering to? (where can I find it) and how hard would it be to install/remove?

 

God damn thats perfect! Thanks alot for the picture and info!