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Old August 16th, 2002, 14:28   #48
Veteran Member
Join Date: Aug 2002
Location: Round Hill, Alberta, Canada
Default Re: Upgraded Window Regulators: New Pictures and New PDF\'s

1998 NewBeetle TDI, also having window regulator fun in the pass. door.

It seems that the common problem is when both of those clips snap in half, allowing the slider-half of the clips to go up and down on their tracks, and the glass-clamp-half of the clip stays attached to the glass. The window just drops. The regulator moves the sliders up and down without moving the glass.

After taking apart my door, and doing a forensic investigation of the tangled cable mess in the regulator, it seems that first, one clip broke in half, as is typical.

Then, with the regulator trying to move the whole weight of the window with just one clip, the window started acting funny. The people that were borrowing the car frantically pressed the power window switch this way and that, trying to get the window up. Then, the other clip broke. Except the second clip broke in such a way that the glass clamp stayed attached to the slider. The part of the clip that clamps the little lead cable plug broke, releasing the cable, and creating a break in that compound loop the cable goes through. The motor continued to turn the pulley this way and that, in response to the switch being pressed this way and that. The cable tangled up on the drive pulley, and started making a sinister crunching noise. The window finally dropped into the door, and the cable balled up on the drive pulley, and nothing would move.

I have determined that I need a new regulator, which comes with the two new clips. Its on its way, it costs $140 Cdn at the stealership.

In the normal circumstance, where the clips break and leave the cable loop intact, and the regulator does not knit the cable into a ball, you replace the two clips. Then, you bolt the regulator into the door, and using the motor, roll the regulator up and down as necessary to get the clips attached to the glass. The key here is that the power window motor turns a certain number of times around to take the glass through its full travel, and that position of how far the motor has turned relative to the position of the window has not changed.

In my case, the cable loop broke, and the cable balled up on the motor drive pulley, eventually balling up enought that the motor won't turn at all. I have no idea what position the motor is in, relative to the position of the glass.

The question is about how the up/down travel limits of the power window drive motors work. Are there "limit switches" inside the motor drive, that sense how far around the main drive has turned, and stop the motor when the window is all the way up or all the way down? Or is there a sensor that looks at how much current the motor is drawing, and when it draws over a certain amount, it assumes that the window is against either the top or bottom of the slides? Or some other means of travel limit sensing?

In any case, my window is taped to the top, and the motor is unplugged.

I am guessing that given the 20+ wires going into the power window motor drive unit, that the limit switches are in there somewhere. To re-align the position the power window drive uint motor thinks its in with the position the window is actually in, this is my plan:

1. Install the regulator, with the clips in the position where you can get to the clamp bolts through the rubber plug grommets.

2. Lower the glass into the regulator clips and tighten them there.

3. Somehow turn that regulator drive by hand, to roll the window all the way up, tight.

4. Plug in the power window motor drive unit, but leave it unbolted from the regulator.

5. Turn the car on, and using the switch on the drivers door, roll the passenger window up. Except with the power window motor drive unit unbolted from the regulator, it will just spin in thin air until it THINKS the window is all the way rolled up. Turn the car off.

6. Align the splines on the power window motor drive unit with the regulator drive pulley, and bolt the power window motor drive unit in place.

7. Turn the car on, and test the travel. Cross my fingers and toes, hope nothing shorts out, breaks or explodes.

I'm hoping that procedure will do it for me. If anyone has ever done this sort of thing, you'll know what I'm talking about.

If I'm way wrong in my proposed process, please post a reply before Tuesday, which is when the part should be here and I'm going to try and re-assemble this !@#%$ puzzle. If there are any suggestions or corrections to my proposed process, please post.

Thanks. Blue Beetle from Round Hill.
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