Generalised problem...

[davetherave]

Hi,
Just a couple of things, firstly.
My passenger window has now died and not in the up position
Looks like im going to have to wedge it up. (or leave it, surely no one will steal it)
That will be drivers and passenger door without a door card then.

The reason i opened the window was beacuse the heating has now completely failed.

Also the brakes are still doing the thing where you press it and it brakes slightly then unbrakes and carrys on for a bit then brakes again- Scary stuff- any ideas?

And all after i thought id do some cosmetic work replacing the chrome strips, got about 1/3 done!
Have to say this is the first car i have been scared to drive, and my girlfriend is even more scared!

[onthecut]

Hi Dave.

The brake issue sounds like it may be ABS related. On more than one of those I've had built before about '96, I've experienced the situation where you press the brake, it slows down then suddenly lets off for a perceptible period before re-applying. I'm not at all convinced that these ABS systems are fail safe. Have you got any warning lamps on ?

Mike.

[Peter.N.]

Hi Dave

I can't remember the beginning of the brake problem but the only time I had a similar effect was when I had air in the brakelines, initially the air pushes the fluid through until you apply a bit of force then the air compresses - giving you no increase in braking effort until the air is at a high enough pressure to push the fluid through again, feels quite scary. On a conventional system you would probably have no brakes at all but because the XM is fed from the high pressure line it will keep putting fluid in until the brakes come on.

With your window problem, have you tried swapping the switches? could be the one in the drivers or passenger door, quite a common fault.

Peter

[davetherave]

The brakes probably are ABS related then as ever since i bought it the ABS out of order light has been coming on!

I have tried the drivers door and passenger window switch, but i will swap them before taking the door trim off- will report back in an hour or so! Damn the dark though i need a garage!

[davetherave]

Right well got the trim off. I think the winder has been relaced at some point as the motor was not even secured properly.
It looks completely different to the drivers side and the motor is not a bosch either
Also its a two pin

[Peter.N.]

If the drivers side has 'one touch' operation it will be a different motor assembly.

[xmexclusive]

Hi Dave

The passenger window switches are in series so swapping them is not a good test as it just moves a defective switch around in the same chain.
The rear door window switches have the same plug/wire arrangement just lack internal lights.
Test each of the front switches in turn in a working rear window setup to check if either one is defective.
You can always use a rear one as a temporary replacement for a front one.
If this does not solve things then undo the the main feed plug on the front inside edge of the drivers door.
Check for verdigris, clean up if necessary and spray with contact cleaner.
Good contact is important here as the plug contains one set of feed contacts for the drivers window and two sets for the passenger one.
Do the same with the passenger door feed plug if necessary.
On the brake issue I would be inclined to bleed the front brakes as first option.
A common ABS fault is loss of 12v feed. As I remember it needs supplies from 3 seperate fuses.
Any one missing and the light is on permanently and the ECU cannot be seen to read or faults.

John

[Dieselman]

If the ABS light is lit the system is disabled, so the weired brakes can't be that. It does sound like air in the system still. Try an extended bleed with the suspension set to high and running the excess fluid back to the tank.
It sounds like the system is sucking air in.

When I looked at this car I noticed the passenger window switch was out of the door card, so I suspect soemone has already had a go at the window mechanism.
The brakes didn't show the delayed trait though when I tried them, albeit only whilst manouvering. Good job really as I would've taken out someones garage door if they had...

[jonathan_dyane]

It is true that ABS should be disabled when the light is lit, but does the light remain illuminated after starting, or come back on whilst driving?

The reason I ask is that a BX I used to own developed an ABS problem where the light would come back on whilst driving, but before that happened I used to have the problem of the brakes easing off which caused a few unpleasant moments before I pulled the ABS fuse out...

[xmexclusive]

Hi Dave

Check that the ABS light blinks on switch on.
If it lights up without any blinks then the light wiring has an earth problem and the ABS may or may not be working.
If the light blinks on start up the ABS is running through the start-up checks. If the light then stays on the ABS failed the start up test.
If this happened the ABS should be disabled automatically.
If the light blinks and clears at start up but comes alight while running then the ABS is failing the running test due to either an intermittant fault or more likely accumulation of too many temporary faults in the ECU. In the latter case if you get the ABS ECU fault cleared just before a MOT then the chances are it will stay ok for the test.
The ABS simply sends a feed from the ECU to operate the light. The ECU does not check the presence or status of the ABS light. Hence my comment that the ABS could be working with no light present or with the light on all the time. The key here is does the light blink, if it does then the light wiring is powered and in good order. Seem to remember reading somewhere that you can interogate the blink sequence to determine mode of failure. Will see if I can find this.
There have been the odd report of XM Bendix ABS still operating with the ABS light on but coupled with intemittant brake loss.

John