My dad drove a lot of different cars home from his garage. One morning in 1963, I remember looking down the long dirt road in front of our house at the approaching school bus, and I glanced over my shoulder at Dad while he slid behind the wheel of a long black car to leave for work. I still don’t know if that grand old boat was a Cadillac or a Chrysler, but I do remember the goose bumps I felt when I saw all four of the windows slide down into the doors under their own power. When I was 6 years old, it seemed more like magic or science fiction than reality.
The 2004 Honda Civic driver side window has an integral control unit and two relays to operate the driver side power window for auto down function. Notice the motor is a four-wire unit – the second pair of wires feeds a pulsed signal to the control unit for auto-down function. No initialization procedure is listed for this system. Presumably, the control unit simply looks for the pulses to stop and uses that interruption to stop driving the window when it stalls during downward travel. The power window relay in the instrument panel fuse box provides B+ voltage to all the window switches but only in the key on and start positions. Notice also that there are 3 different fuses that can kill the power windows and the all-too-familiar circuit breaker integral to the motor.
According to some sources I found online, Daimler first introduced electric windows in 1948, but the SAE timeline credits Lincoln with the first power windows in 1946.
My wife is a drive-through bank teller, and she says one in four of her customers have a driver side front power window that is inoperative; they have to open the car door to do business. Any shop owner knows there’s a big profit in power windows.
The old scissor-type regulator with its curved rack and spiral spring were by no means trouble free, but they didn’t drop like flies the way so many of the cable and pulley units do nowadays, either. Usually all it took on those units was a motor or a switch. That being said, those units do tend to bind up as the door housing gets tired. And the cable and pulley units are easier to service and from the design side of things; they’re a lot easier for automotive engineers to work into a variety of door shells.
This 1996 Dodge Caravan has a visible motor (usually they’re hidden from view) and two window tracks instead of just one like most power windows nowadays, probably because the door and the window are so long.
For my purposes as a technician at the Ford/Jeep dealer, I’d operate the switch on a dead glass and watch the dome light or the instrument cluster voltmeter. If it reflected a heavy battery draw while I was trying to get the window to move but the window didn’t respond in the desired direction (down if it was all the way up or vice versa), that generally meant the switch was working and the circuit was complete, so a motor was in order. In those cases, removing the door panel and banging the inside of the door really hard will sometimes unbind the motor. If that doesn’t work, you simply can remove and reinstall the motor on a scissor-regulator equipped door would un-jam things for a temporary fix. But that’s all it was. Those just about always came back. Running one of those jamming scissor-types down all the way tends to render it inoperative. I once replaced the regulator and the motor in one of those and the new one seemed to work fine for a couple of weeks and then jammed the same way the old one did, indicating a problem with the door itself.
These two-track regulators can be confusing at best, so it’s a good idea to get the new one in hand and note the configuration and routing of the cables before diving headfirst into the job. Notice that this Dorman replacement (just over $100) has a pigtail instead of an integral connector, which doesn’t hurt a thing, but be careful to keep the extra wire out of trouble.
If, however, operating the switch doesn’t dim the dome light, then there’s an open circuit somewhere. Nowadays, almost invariably, what we have are cable and pulley regulators with a motor that still runs, but the regulator it’s bolted to has become a tangled mass of junk. The most odious circumstances revolve around a window that’s down and won’t go up in a rainstorm or in cold weather; like a bad timing belt, those failures don’t generally pick a good time to happen
The original regulator had become uncabled, as they usually do. She lost this one first, then her right front and decided to get those two replaced before the other two failed. These regulators are a lot quicker and easier to replace than the old scissor-and-spring type.
Troubleshooting becomes more challenging when you factor in the solid state one-touch-down box or body computer (whatever applies), though those little rascals are generally pretty reliable. Some newer vehicles (like the 2006 Sonata) actually have one-touch up windows. That sounds pretty dangerous, doesn’t it, sort of like a glass guillotine? Not so on the Sonata. Those windows are kind of like your garage door; they stop and reverse direction if the window opening is obstructed before it reaches the top of its travel, and there are multiple safeguards built into the ECU programming (see inset).
Motors and regulators obviously aren’t the only problems with power windows, though they’re generally the most expensive repairs. I say generally because some Japanese cars can have pretty expensive switches. At the time of this writing, I found that the drivers side switch on a 2004 Camry lists for $356.67 (the regulator is only $101 and comes separately from the motor, which is $280). The same switch for a 2001 Jeep Cherokee lists for $139. A 2001 Mazda 626 driver side switch runs just more than $300, but that same switch for a 2004 Six is only $104. Go figure. On a 2004 GMC Envoy without heated seats, the driver side switch is $229.83 (the driver’s window motor is $115). Regulators are all over the place, from a little more than $100 to well over $300 on most of the cars I checked. Volkswagen switches and regulators tend to be less expensive, but the window motors on a 2001 VW GTI are $319. Speaking of German cars, the window regulators, motors and switches on Mercedes automobiles are very reasonable, usually costing only a fraction of what those parts sell for on Japanese platforms. The window regulators on Jaguar automobiles run from $600 to $700, and the motors can be about $50 on either side of $500. Can anybody say “ridiculous?” This could go on for awhile, but you get the picture. Fixing the power windows on some cars can be more expensive than a salvage yard engine for the same car.
Moisture barriers like the on on this mid-90’s Mitsubishi Montero are the first thing you see when you pull a door panel on a previously untouched vehicle. They were made of special paper on older cars, but were upgraded to plastic about 20 years ago. And while it’s very tough trying to peel one out of the way without destroying it, the barrier is really important, so do what you have to in order to seal it up again like this when the job is done, even if you have to repair the torn barrier with packing tape.
Ford power window motors that drive those old spring-and-scissor regulators have breakaway gears that are prone to give out, and when I operate the switch for a particular window hear the motor running but not moving the window and making that bumping noise I know the gear is shot. While they weren’t available initially, nowadays, aftermarket gears can be bought at the dealer parts counter as well as at most parts houses. Further, the gears aren’t that expensive (about $20). They’re fairly easy to change, but the labor charge is about the same as replacing the motor.
To do that on an older Ford, just yank the door panel, look in the general area where the motor is located, and you’ll find three center punch marks that correspond with the screw heads that hold the motor in place. You’ll need a 3/8-inch or larger drill bit to make a hole big enough to egress a ¼ inch drive 5/16 socket. After you drill out the center punch marks, just look through the holes and there are the bolt heads. Sometimes you’ll have to remove the door speaker to get the motor out.
This was one of two regulators we had to replace in a 2002 Trail Blazer. While we ordered the left rear regulator, we got a right rear one to start with, and it took the parts guy at the local Chevy dealer three more attempts before he got us the right one. The part number kept changing and what he kept sending wouldn’t fit.
The bumping and thumping that comes from those failed Ford gears results from the fact that the outer gear and the inner gear no longer are turning together. The little plastic pucks that marry the two-piece gear together tend to crumble, and they look as if they are designed to do exactly that, possibly in case of an overload situation, but I’ve never seen that in writing. The helical outside ring gear on the business end of the window motor is driven by a worm gear to provide the necessary torque to raise that heavy glass (albeit with that powerful spiral spring adding lift), and the inner pinion gear meshes with a curved plate that is a part of one side of the scissor regulator.
Power window switches are generally wired in series the way you see here. For that reason, a bad driver side switch in the master power window switch assembly can cause the passenger side window motor not to work from either switch. Both wires feeding the motor should show ground whenever both switches are at rest. If either wire doesn’t show ground, check the wires coming from the master switch. If they both show ground on the incoming side of the passenger switch, then the passenger side switch is faulty. If, on the other hand, there is no ground being fed to the passenger side switch from the master switch and the wires are good, the master switch is faulty. Remember now, if either wire is shorted to ground, the window will work, but only in one direction. I’ve seen that a time or two.
We fix quite a few power window problems in my automotive department at the college. Late model GM cars have lots of power window problems, and at the dealership it generally costs about $400 per door to replace the regulator, which comes with the motor, but it’s a bolt-in part instead of being held by rivets like the Crown Vickies and rear door regulators on late-90s Ford Explorers. For awhile, Explorers used the scissor-type regulators in their front doors and the cable and pulley units in rear doors. Late-90’s Dodge Caravans have cable and pulley units, but with two tracks instead of one, and they can be a bit confusing to figure out if you aren’t paying attention when you snatch the old one.
Crown Victoria window regulators are the same type but are available from aftermarket sources (like Dorman) for a fraction of what it costs to replace a GM regulator, and Dorman is making more and more replacement regulators available all the time. One example of a fairly recent Dorman release would be the front window regulators on some Chevy Trail Blazers.
If a power window regulator is riveted in, there’s no good reason not to rivet the new one in. The plastic insulators that go on either side of the door glass where it attaches to the regulator on a Crown Victoria are available from Ford. The outboard insulator has a big metal washer built into it and the inboard one is all plastic. But when you buy a pack of each, one pack comes with eight pieces and the other pack comes with seven. I’ll never understand that, because they’re always replaced in pairs. And by the way, removing the glass from the door is a must when replacing a cable and pulley regulator.
In a situation where the parts have to be ordered but the customer needs to drive the vehicle, the window can usually be propped up like this with a piece of PCV pipe cut to the right length and notched on the top end to receive the glass. Notice we wire-tied this one to the door to keep it in place.
Then there are those times when we’re blind-sided by motors that need initializing, like the rear windows on Explorer Sport-Tracs. Those aren’t plug and play, so dig out the shop manual if you have to replace one. We did some work on a 2007 Toyota Avalon a few weeks back and found that the sun roof goes offline until the windows are reinitialized, a process that is simple once you’ve done it but impossible to figure out if you haven’t. It goes this way:
1. Operate each window from the respective switch. From full up roll, the window all the way down and then all the way back up. At this time, the driver’s door power window switch illumination blinks.
2. Push the driver’s door power window switch and lower the window halfway.
3. Pull up the driver’s door power window switch until the window closes, and continue to hold it up for more thanone second. At this time, the driver’s door power window switch changes from blinkingto constant illumination.
4. Check for the proper operation of the one-touch open and close function by fully pushing the switch down once and fully pulling the switch up once.
5. Repeat steps two through four on each door’s power window switch.
6. Check that each door’s power window switch light is on.
Dad’s Chrysler might have seemed like Sci Fi, but today’s cars give new meaning to the term “Rise of the Machines.”
Hyundai Sonata Driver side Power Window - Auto-Up and Auto Down – How does it work?
When driver door power window auto-up switch is operated on the Sonata, the “Safety Function” is activated.
When the ECU detects the force of 100N (Newton Meters?) during the window rising (4mm to 250mm from the top of the opening), the window is reversed until 300 millimeters (12 inches) from the top of the door. The Hall Effect Sensor provides input to the ECU on the position of the glass. Notice that there is a lot more to this power window lift unit than just the motor.
Manual-Up/Down function is available
Auto-Up function is not available
Initializing the window motor:
Start with the window in the full open position, raise the window, holding the switch in window full close position over 0.2 seconds. If you don’t start in the full open position, this probably won’t work.
Note: If you initialize the safety power window with the glass jammed, safety function will not be available.
Fail safe mode initializes when the window is forced to move by something other than motor operation - the ECU knows from the Hall Effect switch input that the glass is no longer where it should be. At this point, the ECU enters fail safe mode for user’s safety. In Fail Safe mode, the window will go down but it will only go up 20 millimeters at a time.
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