Mk.2 O/S window motor

[Masterclock]

Hi All,

Looks like the electronic sequential control module has died. Pressing any button results in a loud sqealing sound, with no attempt of the motor turning. Sounds like a relay chattering. Anyone got a spare?

cheers,

Ian

[noz]

Ian,

Before condemning the control module I'd take a look at the motor in the mirror. For the normal non-indexing mirror motor there are only three wires;- common, vertical motor, horizontal motor. For the indexing mirror there are two more wires coming from a potentiometer on each of the axes. The potentiometers provide feedback to the module so that the module knows where the mirror is.

In my experience I have found two common problems:

Feedback potentiometers
These fail, not electrically as you might imagine, but on the plastic drive shaft from the motor. Although I have tried to repair these I have never been truly successful. The problem is that if the potentiometer lies to the module about the true position of the motor then the module continues to drive the motor past its mechanical stop. This results in the teeth on the nylon rack and pinion assembly being stripped. This could be the source of your squealing noise.

Rack and Pinion Assembly
As described above, even if the potentiometers are repaired the chances are that the teeth on the rack have been stripped by the pinion or vice versa. I have never managed to find a suitable cure for this other than taking the pinion out of a non-indexing mirror motor and replacing the stripped rack in the faulty one.

Hope that helps. I assume you know how to get into the motor but if not, please come back and I'll describe the process of removing the mirror glass.

Cheers,

noz

[citroenxm]

QUOTE (noz @ August 01, 2012 10:22 am) 

Ian,

Before condemning the control module I'd take a look at the motor in the mirror. For the normal non-indexing mirror motor there are only three wires;- common, vertical motor, horizontal motor. For the indexing mirror there are two more wires coming from a potentiometer on each of the axes. The potentiometers provide feedback to the module so that the module knows where the mirror is.

In my experience I have found two common problems:

Feedback potentiometers
These fail, not electrically as you might imagine, but on the plastic drive shaft from the motor. Although I have tried to repair these I have never been truly successful. The problem is that if the potentiometer lies to the module about the true position of the motor then the module continues to drive the motor past its mechanical stop. This results in the teeth on the nylon rack and pinion assembly being stripped. This could be the source of your squealing noise.

Rack and Pinion Assembly
As described above, even if the potentiometers are repaired the chances are that the teeth on the rack have been stripped by the pinion or vice versa. I have never managed to find a suitable cure for this other than taking the pinion out of a non-indexing mirror motor and replacing the stripped rack in the faulty one.

Hope that helps. I assume you know how to get into the motor but if not, please come back and I'll describe the process of removing the mirror glass.

Cheers,

noz

Mirror Noz?? Ian is after a Window Winder unit..

Theres TWO sorts.. WE need to know your exact year of car, even better RP number which on early cars is on the passenger front door hinge pillar...

The winder units changed in 1996 around N reg to anti pinch One touch from just One touch... The control box on the later winder is built into the motor, where its seperate on earlyer setups..

[noz]

Doh, Its been one of those days. I read that as Mirror Motor for some reason. Too much alcohol I think......or too little

Apologies,

noz

[xmexclusive]

The XM car in Masterclocks list requires a 9 pin winder module to suit a PSA red slide plug.
The earlier version with the Citroen spring clip locking has the same contact pins but different polarisation.
If you bodge the polarisation the plug hangs underneath the winder with no locking.
If you force fit the wrong one you break the plastic of the plug and the socket.
Neither are ideal options.
For the brave you can swap the motor/controlbox bodies over to change the type.
These winders do turn up on ebay but are usually expensive.
Try NDB Autos as they have some reasonably priced XM bits on offer.
Norwich Tel 01603 618934.

John

This post has been edited by xmexclusive on August 01, 2012 08:44 pm

[Masterclock]

Thanks for the replies,

I should have added a bit more detail. Car age and RP number is in my signature. It is the later cam-lock connector with the red slider and is anti-pinch as well as auto start stop etc.

I did get cought out by one thing when testing the wiring, and may be another difference between the older spring clip connector. There are four wires from the switch that connect the four functions full open, full close, part open and part close, to the motor contol unit. There is also a battery feed and earth to the switch to provide lighting. In the drawing I have the switch is shown as connecting battery to any of the four control lines on depression of the appropriate switch. I spent an age going around looking for missing voltages, before checking again and finding that my switch puts out an earth on the selected control line. Just one to be aware of.

Ian