How to remove the motor and regulator from a rear door

I have both the Haynes and the official Jaguar manuals, but neither adequately described this process, so here is

How to R & R the power window motor and regulator

This is a 1985 Jaguar Vanden Plas California model.

First a note about the door panel. Just slide the top of the arm rest toward the rear of the car. There are 2 screws partially driven from underneath into a wood base, to which the pad is attached. The heads of these screws engage a grooved metal tang located under the pad. The amount of difficulty you will encounter pushing the pad toward the rear of the vehicle will depend on how tightly those screws engage the tangs, but they should be just snug enough that normal use will not allow movement of the pad. A downward and rearward slap or push should free the pad.

My problem turned out to be with a switch, not a burned out motor, so you are strongly urged to use a voltmeter to test that you get voltage to the wiring harness when each of the front and rear window switches is pressed in each direction. Although you might guess that the red wire to the motor is the positive lead and the green wire negative, the opposite is true. With the positive lead of the voltmeter connected to red, the negative to green, the ignition key to position 1 and the master switch "On", I got a negative 12 volts reading when each switch was pushed for "Up", but no voltage in the "Down" position. "Down" should have shown a positive 12 volts.

In my case, neither the front nor the rear switch would cause the window to lower. I found that the rear switch won't work if the front switch contacts are corroded, so the solution in my scenario was to clean the contacts of the front switch, which is located on the "ski slope". To fix a switch, you must remove the glove box located in the center console, remove the (single) screw that holds the ski slope in place and rock the ski slope gently to free it (because time creates a bond between the vinyl and the metal). Be careful not to dislodge any wiring. Now you can depress the 4 tangs on the switch and pull it out of the ski slope. Pry the rocker out, being careful to contain the internal parts. Clean the contacts with a pencil, typewriter or pen eraser. Remove eraser residue. I tied the contacts down with thread and then inserted the rocker with its internal side facing upward so that the spring loaded pins did not fall out. With the rocker reinserted, the thread was easily removed.

Removal

Remove the four #3 PoziDriv head screws that mount the motor and regulator to the inside metal panel of the door. There is a spiral spring just above and between the top two screws. The window must be down from the fully closed position by a bit more than an inch in order for the channel to clear obstructions, so if the window is fully closed, manually push it down and use tape to keep the glass from dropping down further. Now grasp the motor and regulator assembly and push the top toward the front of the car. This will disengage the regulator from the channel so that the assembly is freed.

Note that it is possible to remove the window motor from the regulator without completely removing the regulator. Tape the window in its fully closed position. Push the regulator toward the rear just enough to start a screw into the top rear hole in the door, threading into the front hole in the mounting bracket such that the spiral spring is to the rear of its intended opening. Do not tighten too much, but snugly enough to keep the assembly from rotating. If you allow rotation, the regulator will come out of the channel, which is what you are attempting to prevent. You should be able to see the three hex head bolts that secure the motor and gear to the regulator assembly. Remove these with a 10mm socket and gently pry the gear from the ring sprocket into which it fits. Do not remove the Torx screws that affix the motor to the gear. There are no serviceable parts there. You will find two plastic plugs in one end of the motor. If anyone knows their purpose, please explain in an Email mesage addressed to gypsy at iswest dot com.

Refit

Note that the regulator has a square nylon glide that fits into the channel. Reassembly will require that you fit the glide into the channel by holding the glide so that the flats are parallel to the channel into which the glide must fit. I found that keeping things together was assisted by carefully and slowly running the motor to lower the window to near its bottommost position after sliding the glide into the channel.

The plastic/mylar sheet is a moisture barrier and must be firmly pressed against the metal ("dressed") before parts are bolted back into place. This sheet is held in place with a gooey "glue" that never dries. It needs to be dressed before you insert the screws, but dressing the plastic tends to move the glide out of the channel. It is therefore recommended that you align the bottom two holes in the plastic with the screw hols in the door. Then start one or two of the bottom screws loosely and dress the plastic as well as you can, making sure the original screw holes in the sheet align. Raise the window and finish dressing. Now, Reverse the above procedure to refit.™

Completion

Before you replace the door panel, be sure to test that everything works. Test the locking mechanism, courtesy lights, and both the inside and outside door handles. Make sure the window goes all the way up and all the way down (remembering that the window does not actually go all the way down...).

If you decide to lubricate:

I recommend graphite rather than oil in the channel because the channel will accumulate some amount of crap that oil will turn into an abrasive sludge.
Use grease on the regulator, avoiding the nylon glide.
Use a teflon or silicon lube on the latch and lock parts. I like Tri-Flow TF20006, which is made by The Sherwin Williams Company.