The right rear quarter window on my 1993 XJS convertible has quit working. ( now in the down position ) . I have read on this forum that sometimes it may be as simple a fix as tapping the motor with a long screwdriver. Where is the motor accessible from? The rear luggage compartment, the boot or the window slot?
Thanks in advance
Frustrated in Vancouver

 

You take the side panel off. If yours has a screw between the panel and the window, you take that out and the panel should pull out. There are 3 push studs along the side facing the front towards the door. The motor is behind the plastic water curtain.

https://www.jaguarclassicparts.com/u...onvertible-2-2

 

The problem : [in my experience of one car] is caused by the window regulator being driven to wound & jammed down by the motor, gravity and inertia. To go up from this stationary jammed it only has the motor hence does not sufficient power. Using a new motor with more power will not help as it will be jammed down with more power.
Free run current is around 5 amps down , similar up with jammed down and jammed up current around 20~30 amp.


Hitting the motor: May work if the motor brushes are not making contact with the motor armature. Hitting is unlikely to free the motor & regulator assembly from a wound to jammed position. In either case hitting will reduce the magnets strength & probably fracture the magnets within the motor and will not provide a long term solution. As above a new motor is also unlikely to provide a long term solution either if the problem is due to jamming.


To confirm if the motor is working:
The motor has two wires going to it so a 12v battery will power the motor up or down from a free [not jammed] position by reversing the two wires. This will probably not free a jammed assembly. You will be able to tell [without a meter] if the motor has a circuit as the wires will spark a little on being connected. If the motor is open circuit [crook brushes, armature or wiring] then no spark will be evident. You may free a jammed down 1 out of 5 times if you are lucky by tap tapping the connecting of the power to up.
Unfortunately you will have no way of easily knowing if you are actually powering up or down. You can figure this out by metering the motor wires while up is commanded and duplicate this polarity to be sure you are powering window up & not down.



To Access motor & regulator : in an easy approx 15- 20 minutes, the motor and regulator assembly is accessed [removal is extra 30 minutes] by removing the three screws and chromed cover trim & disconnecting the courtesy light adjacent to the window slot [roof retracted is easier due to more room and light but not vital]. Note the long screw on top.



I fully extended the seat belt and tie a knot in to prevent the belt retractor pulling the belt and cover from out of the way and soiling the belt.


I used a hair dryer to warm up the plastic rain cover under the chrome top for ten minutes [you deserve a cuppa] and remove the three plastic plugs [with a flat screw driver then long long nose pliers] to allow the plastic rain shield to be removed. Now the motor can be accessed if you decide hitting it is for you. I'd suggest the handle not the shaft.



To remove motor and regulator:

7/16 & 10mm spanner and 1/4 drive socket set [from memory] will remove the motor and regulator.


In my experience removing and manually unwinding the motor will not fix the problem as it will jam again next time or when you are out with your mates on a trip away from home with rain due.


Fix:
I fixed both sides by fitting a limit switch in series with the down relay winding on each side.


Now when the window is commanded down 5mm prior to hitting the mechanical stop the limit switch in series with the down energized relay winding stops the motor power. This eliminates the driving to jammed state [including the additional approx 2 ~3 seconds of window controller driving the window motor and regulator while stalled fully down on this car]

I left the fragile internal plastic covers off for three months after fitting the limit switches in case there was further problem, there was not.



Conclusion:

With limit switches fitted to down on both sides and used for a summer, no jams at all so far with original motors still in play. Even with sufficient confidence to be driven on a rally a day & a half's drive away from the home shed and put the top down.

 

Hit the motor how? how did you get to the motor? Hit it with what? how hard?

 

I use a lo-o-o-ong screwdriver that I keep in the trunk.

Just bang on it a few times. As hard as seems reasonable. Don't be gentle, but you're also not trying to break it.

 

OK, definitionally just how long? Also, are you banging while trying to close the top, that’s when the window should start to raise? I don’t even know what it looks like to bank on and I have heard some people say the mother is encased in plastic? I assume that plastic housing needs to come off?

 

Mbower1967,

There's 2 ways to get to the motor:

- Through the vent in the B-Post
- By removing the inner quarter trim as described in the post immediately before yours.

Cheers

Paul

 

Tap it a couple of times, then see if it works again. Remember, you have to operate it with an 8-second delay on that convertible roof switch. So youre going to tap it a couple of times, then see if the windows go up and down. I'd put the top down, then place the pump in manual mode, so you're only waiting for the quarterwindows to do something without needing the top to come up/down.

You will want to know what you're looking for, so see if you can look up jaguar xjs quarterglass motor on ebay or something, so you know what you're looking for. I have never been able to remove my vent, so I take the trim off to expose it, but now that I know what I'm looking for, I can do it with the screwdriver without taking anything off!