reading the sticky on door cracks, the second to last post says this:
"One thing I noticed is when the express down module for the driver window goes bad, the regulator stresses everything. It'll eventually start affecting the door skin itself."

on my 2002 Firebird. my driver window goes down way to fast and it seems to go too far down and i can see it flexing the door. Almost like something is hitting the bottom of the door and pushing and twisting things. so, as of now, i simply use the express down, and manually stop the window shy of all the way down.

i bought a new regulator and motor and will be doing a swap.

my question - what exactly is the "express down module"? is it the switch on the door? or is it something in the motor?

i look forward to any help.

thank you

also, i heard that there is suppose to be a foam piece inside the bottom of the door. if this is the case, mine is missing. is there actually one there?

 

There's a rubber bumper in the bottom of the door shell the glass bottoms out on. There is also a front and rear stop at the top of the door that limits upward travel. There are also guides at the top edge front and rear of the door that adjust the lateral movement of the glass.

As far as the door flexing at full down that's normal these cars have done that since day 1. I have had a few modules that fail cease to operate but none that have failed to cut the motor off on full down that could cause motor and door failures. But, that's not to say it won't or hasn't happened.

 

does that rubber bumper cause resistance to tell the window motor to stop?
i have no bumper and it appears my window (or the mechanisms) goes all the way down, hitting the bottom of the door, thus pushing up on the regulator thus flexing the door.

i tried to find that bumper before to purchase, but if i knew the dimensions of the bumper, i can install one once i install my new regulator and motor.

 

That thought is in other places throughout the thread. The thread has some good info and some bad info, also. This particular point is a red herring, without any supporting facts. I have yet to see a post on this site with a problem related to the door "bulge."


Of all things you could do to the door, this replacement has the highest chance for doing damage. The regulator rivet holes are particularly sensitive, as is the door skin to the rivets. When replacing the regulator, you need to:
- Be VERY careful drilling out the old rivets so you don't elongate the holes in the skin or grind them up.
- Rivet the new regulator in with the special rivets (sold at GM dealers) made specifically for the door skin. (They have an uncommon size and are aluminum w/ a steel mandrel, which is also uncommon.) These rivets will require you to have an oversize/industrial pop riveter. Nuts and bolts will do damage to the door.
- If you take the old motor off the old regulator - make sure you mechanically lock the regulator so it doesn't spring on you and take off a hand.


From the factory, one was only installed on the driver's side. It is a package of electronics that puts the glass full-down with a short tap of the window button. The module itself sits in a plastic pocket on the side of the trans tunnel.

This isn't the source of the door panel problem, either.


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You might compare both doors to see what you have. This bumper often falls out of its slot and rattles around the inside of the door. You might take out the speaker and put your head in there to see if it's rolling around inside the door.

Most importantly, this part will keep the glass from rattling when the window is down. It might also stress the door in a different way than without, but it wouldn't have anything to do with the cracked door panel.


The door panel will move, flex, and bulge in a number of different ways. The real problem is that the staple holes for the weatherstripping at the top of the door are too tight and don't allow for this movement.

 

The bumper is to cushion the glass as it bottoms in the door on downward travel. All the module does is see the amperage spike as the motor bottoms and then cuts power to the motor.

 

The express down is not the switch. It is a module in the dash. It is supposed to sense the window is down to shut off the motor. If it doesn't shut it off this could cause premature regulator or motor failure not to mention stress on the door.

 

is there a way to test the module?
any idea where I can get a new one?

 

Observing it is the best way put a dmm on window motor roll the glass down at most motor should stay energized 2-4 seconds or so once glass bottoms out.

 

You'd have to probe the wires coming out of the module, connected to the motor.

 

Or pull the drivers door panel and hook your dmm to large dark blue and large dark brown you can get to it there also it's exposed where it goes through the door skin by the speaker. In down position brown has power and dk blue is ground