Repairing Your Fiero Power Window Motor
By Chuck Kichline
(Larger photos under all the thumbnails)

I knew I was in trouble when I pressed the passenger power window button, and the window went down half way and started to grind.  If it just hadn't worked, I would have figured it to be an electrical problem, but this was obviously mechanical.
I did manage to get it down and up, by grabbing the window and forcing it past the dead area, but THAT wasn't good enough for real life, so I decided to pull the power window riser.
I found both my Chiltons and Haynes manuals to be just about worthless so I went out on the web.  I couldn't find anything to help except several how to's on replacing manual windows with power windows, but at least that was enough to get me going.


First problem is getting the riser out.  As complicated as the instructions on the web are, I found it even harder.  I ended up knocking out seven pop rivets and unbolting the rear window channel.  I have a bigger photo linked to the above thumbnail that you should look at.  I had to remove the five motor mount rivets as well as loosening the cross bar and swiveling it out of the way, and the top power lock bracket rivet.  See what's circled in the bigger photo.
Even after that, I had to have an act of congress to get the motor past the lock solenoid.
You need to fix the window so that it doesn't fall down.  I used C-clamps and rags on the edges of the window glass to hold the window up.  I'm told that another good way is to use duct tape where the window comes out of the door.
To get the BIG pop rivets out, grind the top flush with the head, THEN hit the center with a punch.  It should pop right out.
Oh yea, nobody mentioned it, but there is a connector at the base of the motor.  It is locked in by a long press bar that's at the bottom of the assembly.  I ended up cutting my wires, and didn't need to.


The unit looks like this, pardon the shadows, but it was about 100 out when I did this, so I was looking' for shade.
I could run the riser motor out of the car, and verified that the motor would run the riser up and down, but would skip when it got to a certain point.  This verified that there was a problem with the gear train.
If there was ever an inseparable assembly, THIS is it.  But, I figured I should try to fix it if I could, so onward into the assembly!


Here's the assembly, disassembled.  I had to grind and drill about 10 rivets and folds to get it apart.  What I found is that the black gear near the center of the photo had lost a couple of teeth, probably because it was near the top or bottom of the action.  It effected the action about three times in a cycle - top, middle, and bottom.
I did what I could to repair the assembly.  I rebuilt the missing teeth on the black gear with epoxy, then ground them and reassembled the motor.  When I reassembled it, it whined like a mechanical alarm!  I just wasn't going to be able to fix the motor assembly.
I did find though, that you can remove the plastic brush holder (far left of the photo) from the unit by bending three tabs on the bottom of the motor.  If your unit has quit and you've verified that it's not an electric circuitry problem, it might be worth it to remove the riser and remove the brush holder and check the brushes, they could probably be replaced with a little work and luck.


Next thing was to look for a replacement motor.  I did some searches on the web, and found that the motor unit assembly was an aftermarket part!  I found this unit IN STOCK at my local AutoZone store new for $50.  Obviously, the unit is a standard part for many GM cars.  The included bracket is not used in this application.
Onward to installing the riser from my old motor.


Here's photos of the riser removed from my old unit.  A couple of hints are to MARK the relation of the motor bracket and the gear arm.  It will make the assembly back into the door easier.  Before you remove the riser from the old motor, also remove the big spiral spring.  Mark the direction of spring spiral onto the riser so you get it back on the right way.  BE REAL CAREFUL with the spring.  It's big and could easily bite you.


Here's the reassembled power window riser unit.  I used small nuts and bolts in place of the original rivets.  Three rivets hold the window riser and two hold the small bracket on the end of the motor.  If I'd had the right size pop rivets, they probably would have worked too.

Now all you have to do is reassemble the unit back into the door.  You already know how if you took it apart. I could only get to the back of three of the five mounting points to install bolts with nuts.  There was a very good hint somewhere about using large self-tapping screws and then grinding the ends off after you've gotten them to start their own threads.  I'd do that if I had had the screws.  Meanwhile, I'll see if it works this way.


Door is back together, the window goes up and down, and it's ready for a good cleaning.  One more Fiero mystery exposed.  If anybody has additional info, I'd like to add it.  Just send me your comments!

"Permission to Publish"
In any newsletter or web site, with credit.