Repairing

Power Windows Won't Operate

Page Revised: 10 May 2019

Mode:

Article by
Eric Dess

Another very common thing to go wrong on these cars (aside from the inoperative dash lights) is the failure of your power windows to operate. Your problem will typically fall under two different areas:

A. The window goes up or down REALLY slow or not at all

or

B. You have seem to have good power but the window still won't go down or up

In the case of A, your motor's contact brushes have probably disintegrated. Over time, this happens to any sweep-contact type of motor (your alternator and voltage regulator are another example of this). So it's not anyone's faults except for Father Time and usage; quite a normal thing really. Good news is, you can get the motor rebuilt, or perhaps be able to hunt one down in the salvage yards. Or you can even buy them new at the Ford dealer (beware of sticker shock), through parts stores, or via eBay. Buyer beware, however: we've experienced bad new aftermarket motors from eBay.

If you're the adventurous type and would like to diagnose the problem yourself, here's how to do it. First, remove the door panel and insulation, and find the wires going to the power window motor. They're on the bottom, in the hole toward the front of the car, and should be either pink/black or yellow/black in color. Next, determine the power wires—you'll have two:  one to make the window go down, the other for going up. Skin back each wire a bit (usually about 1/2" is sufficient), and turn the ignition key on but do not start the car. Then you'll need a 12v battery charger. Touch the 12v positive clamp onto one wire, and the 12v negative on the other wire. (Might have to use trial and error here). Your window should go one way or the other with no problem. Then, do the opposite—touch the 12v positive clamp to the opposite wire and the 12v negative clamp to the remaining wire (reversing polarity). The window should go the other direction smoothly. If all goes as written here, that means with a pure 12 volts going to each direction, your motor is not putting out 12v, and that indicates a rebuild (or replacement) is necessary. Nine times out of ten, this is the culprit. (Be sure to properly tape up the exposed wires before going any further). Now for some reason, the window always seems to go up and down slower than stock after a rebuild. But they can be very inexpensive; we've paid as little as $40 for a rebuild. Quite a bargain, especially since you don't have to risk cutting yourself up.

However, if you want to tackle a motor rebuild yourself, Robert has pass along this information: "I had a different failure and it happened on both windows over time. The motor worked fine but the gears inside had completely broken. When searching for the parts to fix it, I found them labeled on RockAuto.com and at Autozone over the counter under window regulator - Dorman part number 74426. It's basically a 45-tooth gear with a 9-tooth gear glued to it. The failure occurs when the glue connecting the two gears fails which allows the gears to spin independently of each other and thus the window will not go up and down. I ended up drilling out all the regulator and window glass rivets and removing the entire regulator and the window glass, but in retrospect it might be possible to get to the motor alone without removing and having to reinstall all that. If you do remove the regulator, it is spring loaded so you need a helper, and the motor needs to be reinstalled at the center of the travel (thus the need for a helper again). To change the gear in the motor, remove the motor from the car of regulator by removing three small screws. Then you can open the cap and see the gear that need to be changed. To get it out though, I believe you need also remove the long gear screw. I had done it first so even that might not be necessary. If you do need to, remove the two long bolts that hold the cover on the motor case and pull it out. Once you do that you should be able to remove the gear, clean the broken parts and install the new one. To reinstall the long threaded screw with the armature you need to remove the bottom of the motor case with the brushes too. Just knock it off with a screw driver then reset the springs and brushes, insert the armature, then with your helper again holding the motor case, slide it back over the armature making sure the brushes are properly seated. From there you should be able to install the new replacement gear and reinstall everything. Lots of detail work with little parts, plus tons of drilling and re-riveting if you need to remove the regulator but this is a $15-$25 fix if you can DIY."

If your problem sounds like B above, better read up...there are many things associated with this area as well. Probably the most common thing is the window glass physically separating from the plastic clip holding it in (1987-88). Again, due to time, the glue gets brittle then lets the glass slip out. Now it may be possible to use some kind of epoxy to reglue the glass back into the clip, but we've been told by several people that there's not much success in doing that. The Ford garages usually just order whole new windows; the clip comes glued on them already. Plus, to reinstall the clip requires a 1/4" rivet gun, and that's like a $300 piece! Your best bet would be to call or visit an automotive glass specialist and see if they can help you. They can also order the clips in aluminum now, which is much better and way more reliable. Jason has reported that using Gorilla Glue has worked; it's been over 2 years with no problems. Several people note that they got special adhesive from glass shops. The key to getting any kind of adhesive to work is to sand the glass in the attachment area, and to thoroughly clean everything with degreaser before applying the cement. If reusing the plastic clips, drilling holes in the plastic seems to help with providing more adhesion.

Dennis has passed along some information about the above window clip problem. "You can tell your viewers not to bother using any over-the-counter adhesives or epoxies, believe me I tried them all. There is no substitute for the glass adhesive that can only be gotten from an auto glass shop. They don't like to sell it to civilians, because it is extremely toxic and is very bad news if you get any of it on your skin. Once I described my problem to them, they sold it to me. The owner said he repairs 2 or 3 Cougars a month with this problem. Once you have the glue, the job is not bad. The key to success is you have to make sure you get all the old glue off the window before you apply new. The glue cost $8.00 and I'm back in business!"

It's also possible that the regulator (scissors mechanism) could be bent or binding up on some object inside the door. A loose guide or bent door lock rod would definitely do that. Or it could have simply slipped off the track entirely. Whatever the case, if you've got what you feel is good power to the motor itself, then one of these problems are what you're looking for. If you're careful enough you can probably fix it yourself with little effort. All it requires is that you remove the inner door panel and insulation, and you've got access to almost everything inside the door. A little tip: before you reach your arm inside the door, please remember that the metal is very sharp and WILL cut you up in a heartbeat. An old trick is to slit some rubber hose longways and push it over the metal, then you can work inside the door with ease.

Lastly, you may have a bad window switch. It's not a common thing to happen, but if you've accidentally spilled something down in the area of the switch, it could either prevent good contact or short out the switch. The switch can be wiggled off its base and cleaned, in case you need to check it out.

If all else fails, please see an auto glass place—they've run into everything that can possibly happen to auto glass and will have an answer for you.