my 96 ...fan on pass side for AC fuse is removed ..when fuse is placed fan runs irregardless of switch and or ignition. Driver side works with fan switch. Fan switch only operates on high. New switch??? how to remove old one ?

 

Very likely to be the Darlington transistor. There is one mounted each side of the heater unit. This is a typical symptom of failure. Can be replaced with a similar unit from an electronics shop.

Do a search on this or other Jaguar sites for further info.

Good luck

Paul

 

Experienced the same problem on my '96. It was the transistor. The following describes how I fixed it based on lots of research from the various sites. Good luck.
Mitch


1996 Jaguar XJS Driver’s side heater/AC blower replacement
In researching how to do this job, I ran across a posting by Nigel in November, 2002 on the Jag lovers forum. It was the best account I had read on how to remove/reinstall the driver’s side blower on an xjs. I’m not sure what year his car was but the account pretty accurately describes my experience with one important difference, the steering wheel on his car was on the wrong side. The following account is for a left hand drive.
Remove battery negative lead (this did erase my radio’s memory but that was the only issue I faced, didn’t need a “code” to get the radio back up and working)
Removal of instrument panel:

• Remove side trim around instrument panel by removing 1 screw on each side and one screw at the top/middle which holds a small piece which joins the two side pieces. There is trim along the bottom of the trim pieces on each side of the steering column which must be loosened; one screw on each side of the steering wheel fastened from below.
• Once the trim is removed, there are two screws that hold the instrument panel to the body at the upper corners. First, pry out (with your fingers) the two screw head covers; they come out easily. Then remove the two screws underneath. Lower the steering wheel as far as it goes and pull out the instrument panel.
• There are two electrical connectors that attach to the instrument panel. From the left side, reach in and press down on the top and bottom of the left most connector; this releases the connector. Then reach further in and release the second connector by pressing down on the catches at the top and the bottom of the connector; the connector comes loose easily.

Remove lower dash pad by removing one plastic screw on the far left side of the pad and then swing it down , unfasten the strap that wraps around the cross bar in the middle of the bottom of the “scuttle pad” and then unclip the lower clips and remove the dash pad
Remove the two screws that hold the vent/grill on the forward end of the console left side. This will release the small grill and the side cover comes right off
Remove the cross bar that the scuttle/lower dash pad clips to by removing two nuts holding the right side of the cross bar and then two bolts that hold the left side of the cross bar and remove the bar.
There are 4 nuts that hold a bunch of relays and the fuse panel to the blower housing. Remove all four. Two are easily seen below the fuse box. The top two are harder to access and are accessed through the instrument panel hole; one right above the steering column and the other (the left upper one) between (underneath) the duct that runs across the top of the firewall and feeds the left side vent and the big bundle of wiring. The bracket held on by these four nuts has slots in lieu of holes. Therefore, the top two nuts can just be loosened and, with the bottom two nuts removed, the bracket can just be pulled out and down to release it from the blower assembly. Having the two upper nuts installed and loose on the blower assembly before trying to reassemble things makes it much easier.
The blower housing is held on by two bolts. The lower one is on the right side of the blower casing and is fairly easy to see/access. It points down at about a 45 degree angle. The upper left bolt is very hard to see/access. It is about 3 or four inches to the left of the upper left nut that holds the electrical bracket to the blower housing. This upper bolt is also pointed down at about a 45 degree angle. This bolt can best be reached from under the dash with a long extension with a universal joint right before the socket.
Nigel in his November 2002 article, indicated that removal of the side vent and the ductwork that runs across the top of the blower assembly aids in the blower removal/reinstallation. This is correct and a helpful tip. The vent surround is held to the dash pad by two clips, one in the middle of the bottom strip and one in the middle of the top strip of the surround; the clips hold the trim very tight. I removed the piece using a kitchen knife. Once the wood trim is removed, the vent grille is easily pulled out. The ductwork can be pulled out through the vent hole although it takes some doing. The other end of the ductwork just slides off of the section of ductwork that feeds it along the top of the firewall.
Removal of this duct gives easy access to the two electrical connectors feeding the blower. These connectors were tucked up behind the duct.
The fresh air damper along the back of the blower assembly must be held closed to clear the hole in the firewall that leads to the fresh air plenum. This is done by holding the bottom, recirculating damper on the blower assembly open as they share the same linkage. – when one is open the other is closed. With the lower flap held open, the blower assembly can be worked loose and it will drop down.
Once the blower drops down, unhook the blue ductwork that connects to the heater/air conditioning unit right in front of the center console. The blower then is rotated counter clockwise so that the blue ductwork is pulled up and across the top of the steering column. On the ’96, the OBD diagnostic plug, its bracket, and the hood release/bracket (all held to the side panel by 4 screws) gets in the way. Remove these brackets and pull out of the way. The blower then can rotate and can be removed.
On my car, the fan was running all of the time and the previous owner had the fuse pulled. This in turn impacted the operation of the climate control ECU in a variety of ways. The AC didn’t work and air wouldn’t come out of the correct vents when either in the manual or automatic mode. The previous owner had gotten a diagnosis from a jaguar repair shop indicating that the problem was a faulty ECU. With the fuse in, the fan seemed to run at various speeds depending on the fan switch and temperature settings and changing settings and all of the dampers/air flow seemed to work as they were supposed to. It seemed pretty obvious that the blower control transistor had failed shorted to ground.
Once the blower was out, the little blower control panel , a triangular arrangement at the discharge of the blower can be removed by drilling out the three pop rivets holding it onto the blower. There’s a wire clip on the side of the blower that, when removed, gives enough slack in the wires to remove the circuit board. (The blue rubber ductwork is taped to the blower discharge and is easily removed/retaped back on with duct tape).
My circuit board had four components on the inside, two diodes and the 68 ohm resistor, and the case of the transistor. It was easy to check the diodes and the resistor in place. Also, it was easy to check the transistor which was faulty (measure continuity from the case to either pin and then reverse the meter leads. It should read continuity one way but not the other – just like a diode. Mine read continuity both ways; shorted out and hence the cause of my blower running all of the time.
It was easy to unsolder the transistor and remove it and the accompanying capacitor. I bolted in the new transistor (an MJ11016) and soldered it in with a new capacitor (.01 uf, 50 volt); soldering done on the outside of the circuit board (outside of the air flow). I pop riveted the circuit board back into the case.
I reinstalled the unit in the car, hooked up the wiring connectors, reinstalled the instrument panel connectors, hooked up the battery negative lead, and tested the unit before further installation. Everything worked as it should.
Being able to see/guide the socket to reinstall the upper blower assembly to firewall bolt by seeing through the left vent opening made reinstallation much, much easier.

 

Thank you for posting this, it is very timely. I was just told my left blower is not working and there is a leak at the expansion valve. Jaguar wants my first born to repair everything, however they said the parts are no longer available. If they don't have the parts, how in hell are they going to fix it...and what are they going to do with my first born???