Power window motor quality

[Fairlane514]

My question is a little different, and I did do a search toni avail. My truck was missing the passenger side window motor, so I bought a new one from ebay. I cleaned the tracks and made sure the wheels rolled freely but the window is very slow and sometime doesn't make it all the way up. I did check the voltage and its getting full 12 at the switch.

My question........are some motors better than others?  Should I look for an AC Delco?

Thanks

[zieg85]

A poor ground would do that, feel the motor for heat by the plug in and mounting bolts...  Is the window binding or a track out of adjustment?

[bd]

To begin, I think the PM motors are under-engineered (inadequate torque) for the application, which generally shortens their lifespan.  If there's any binding in the regulator mechanism, the motor will strain to overcome it.

Spray the channels with a dry silicone spray, not WD-40.  Grease the sash rail and stationary door roller tracks.  Verify the channels are properly adjusted.  Then check voltage drops with the window operating.  Check both the ground and feed circuits.  Voltage loss across the window wiring and connections is common.

[Fairlane514]

The window does not seems to bind, it starts out ok, then slows down to very slow and stops about 3/4 of the way up.  I will do some more voltage checks.

bd what do you mean by "PM motors?"

[bd]

PM = permanent magnet

Stationary magnets are used to interact with the electromagnetic field of the rotating coil instead of a fixed electromagnet interacting with a rotating electromagnet.  PM motors are generally more compact, lighter, and less expensive to manufacture, but have drawbacks when downsized.

The fact that the window slows to a crawl as it raises indicates that either there's a voltage drop wasting energy as heat or there is mechanical resistance in the lift mechanism that includes the channels. 

After the window slows, if you let the motor cool for a while before continuing, will it speed up again?

[Fairlane514]

I haven't tried letting it cool down, but i could try that.

I just went out and tried it with the engine off, its slow both directions, and only gets about a quarter of the way up and almost won't go all the way down. With the engine on it goes down in a reasonable about of time, but I have to help it with my hand to go all the way up.
I do hear a slight mechanical sound when it goes up and down (slight clunk). I did install a new regulator at the same time I installed the new motor. I will also tell you when I first got the truck and removed the door panel, I discovered a large wooden stick holding up the window. I also saw some damage on the window channel that is on the bottom of the window (horizontal). I repaired the damage and ran the new regulator wheel through the channel to make sure it rolled smoothly.
Also with the regulator out the window moved up and down easily by hand in the vertical channels. 

[bd]

My '87 R10 experienced nearly identical symptoms.  Right side function was much worse than left, largely because of the longer wire run.  After replacing two right side window motors in about three years (and many voltage drop tests), I reconfigured the factory wiring, installing UP and DOWN relays, and used the factory harness strictly as a control circuit for the relays.  Consequently, voltage delivery to the right motor was greatly improved.  I've had no problem with slow windows, since.  But, this is not an end-all repair.  Any/all mechanical binding must be corrected first.  Then voltage drops should be measured and tallied.

On the mechanical aspect, bear in mind the rear channel is adjustable in two dimensions.  Dry silicone spray in the felt channels sometimes helps significantly.

The issue I encountered was due to accumulated voltage losses across the wire run, the switches and the various harness connections.  Essentially, the supply system was engineered with barely adequate current capacity, using all new materials as delivered from the factory.  By that I mean the wiring was of insufficient gauge, and electrical connections, including the internal connections of the switches, had inadequate contact area to supply the current demanded by the motor.  There was no engineered margin for the natural aging of the individual components comprising the system.  Hence, excessive voltage was consumed by the harness in the process of conducting current to the motor, so the motor was chronically under-powered causing it to overheat and fail prematurely.

The problem is quite common.

To clarify some nomenclature, so there's no confusion...  the metal strip attached to the bottom of the window glass is called the "sash," the regulator rollers move horizontally in "tracks," and the glass moves vertically in "channels." 

[Fairlane514]

Thanks bd for your help.  I have some things to check and consider rewiring with larger gauge or relays.

I found a new sash, which may help, because thats what was damaged and could be just enough "off" to cause binding.  What do you think about new factory style switches and wiring harnesses?

[bd]

Having invested 30+ years repairing GM trucks and everything else from VWs to Class 8s, ambulances, fire trucks and coaches, I generally prefer OEM parts and methods for routine vehicle repairs.  The aftermarket generally copies the OEM ...sometimes quite well, sometimes not.  Rarely, the aftermarket will improve on the OE design.  The problem is a 'copy,' more often than not, includes OE weaknesses when they exist.  So, both the OE and aftermarket will use similar wire size for any given circuit.  If the OE was under-engineered, so may follow the aftermarket.  A custom harness will work best under these circumstances.  But, this is just my opinion.

[IdahoMan]

BUMP.

My passenger window wont budge or make a sound (maybe a faint click if you really strain to hear) with the engine off. The long center terminal on the window switch will burn you if you have a finger on it.

When the engine is running, the window moves up and down ok. Not as well as, say, a 94 GMC though. Mine goes up and down smooth but not super fast. It just feels creaky/"old" and RRRrr..RRrrr..RRRrr.. a little.

[Rustbucket86]

BUMP.

My passenger window wont budge or make a sound (maybe a faint click if you really strain to hear) with the engine off. The long center terminal on the window switch will burn you if you have a finger on it.

When the engine is running, the window moves up and down ok. Not as well as, say, a 94 GMC though. Mine goes up and down smooth but not super fast. It just feels creaky/"old" and RRRrr..RRrrr..RRRrr.. a little.

Sounds like the regulator is trying to freeze due to sitting for so long. Engine running puts a lot more power to those windows than when it's off. My passenger side window barely moved engine running, and none at all engine off. I took out the regulator and motor, and sprayed all the joints and the spring in the regulator with pb blaster. After letting it soak in a minute I started moving the regulator up and down till it started unfreezing. Another shot of pb blaster and it was smooth enough for the old motor to move it, but while it was out I went ahead and put on a new motor for good measure.


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[VileZambonie]

Do like BD said, lube everything up and check your voltage drop. May be beneficial to upgrade the PW wiring to a relay system. I think there's a diagram posted on the forum

[pneuner750]

Having invested 30+ years repairing GM trucks and everything else from VWs to Class 8s, ambulances, fire trucks and coaches, I generally prefer OEM parts and methods for routine vehicle repairs.  The aftermarket generally copies the OEM ...sometimes quite well, sometimes not.  Rarely, the aftermarket will improve on the OE design.  The problem is a 'copy,' more often than not, includes OE weaknesses when they exist.  So, both the OE and aftermarket will use similar wire size for any given circuit.  If the OE was under-engineered, so may follow the aftermarket.  A custom harness will work best under these circumstances.  But, this is just my opinion.

BD glad your here to answer questions!  Thanks! !!!

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[bd]

Frankly, there's a lot of experience represented on this forum - some comprehensive, some narrowly focused.  The gentleman posting just prior to you is one of the elite.  There are others similarly considered within their areas of interest.  Everyone here has his/her strengths and something valuable to offer.  Even so, thanks for the kind words.

[LTZ C20]

Modest as he his, BD is also an elite. Rich W also.