Windows go up an inch at a time

[gordonquirk970]

2008 X358 LWB 2.7TDi - All windows will only go up, or down, an inch or two at a time and then only on every 8th toggle of the switches. never 7, never 6 - only every 8th attempt. No error codes to help so is there anyone out there had the same problem and how to rectify it please? It has been suggested that it needs to be "re-set" but I don't know how. All suggestions gratefully received to prevent my mechanic punching me for taking it to him in the first place. Help us both please.

[PaulGover]

I'm not sure exactly what's happening, but the inching is typical of a short press on the button. You may not have noticed that the button has two depths of press - a short press that runs the motor only while you keep the button in that position, and a deeper press that should cause the window to travel to its furthest extent even if you now take your finger off while the window is still moving.

That doesn't help much. Resetting the windows is what you need to do after disconnecting the battery. For each window, press each button fully to first lower the window to its lowest point, and then back to the highest, keeping your finger on the appropriate button until each movement stops, and you should hear a slight click about 1/2 second after it stops moving. (If you don't get the click, repeat the up-down cycle.) That click is the motor turning off having stalled, and I think that's what tells the ECU what the maximum travel is (which is what you are resetting).

That said, counting up to 8 seems weird, and suggests something deeper - wiring issues, switch issues or ECU issues. As it's all windows, likely the ECU. If I remember correctly, the window gubbins are controlled by the driver's side ECU behind a panel in the trim between the accelerator pedal and the door opening. The first port of call is to try disconnecting the battery, getting behind that cover, and unplugging and replugging everything (to "wipe" the contacts), reconnect the battery and reset

[dougiekite55891]

Hi Gordon
Did you get your Windows sorted??
I know post has been up awhile but only just joined
Regards
Dougie

[gordonquirk970]

Thank you both for your reply and apologies for not getting back to you sooner.
I haven't had time to even have a look at it recently but I will start with your suggestions and see if I can "re-set" the windows by either cleaning or replacing the ECU.

leave it with me and I will report back.....

And thanks again.