Pogophil

Well, I'm not sure I actually said it as I was typing it.... and if I did, I'm not sure how you would have heard it....

But yes, I sprayed some WD40 in there to try to loosen up the rusted parts inside, per a few recommendations I received (including one via PM). I also tried some white lithium grease without luck.

Problem? Sounds like you disagree with it (....but WD40 can cure all!).

mdarney

take the motor off the drone gear (two torx screws) and be sure the brushes are moving freely. Clean/ lube as necessary and reassemble. Test with 12 volt source I did this and saved the motors. Mark

Ron_H

I thought you meant something like Liquid Wrench. I have never used WD-40 for internal electric motor parts, and I would not think of using Liquid Wrench on them at all. Maybe WD-40 works. I spray it in a 911 engine I have sitting around waiting for a car that needs it, and turn it over once in awhile. I like the idea of disassembling the motor before spraying that stuff on it, and only on the specific parts in question.

Alan

Sorry - you asked for help and got the same reply from many folks - seems you haven't actually done it yet though... test for power at the motor - there are only 2 wires - if thats good:

Take the motor out! - you are wasting your time squirting wd40 at it/into it...

Support the window in position first - If I recall there are couple of allen bolts or torx bolts holding the motor casing - remove. . pull the casing off clean the inside of the casing and the motor stator/rotor - get rid of any debris & lube the whole thing and reinstall.

This is what post 3 (and others says already...and we are 10 days later at post 18...)

Alan

chaadster

Alan,

Thanks for posting that. I've been watching this thread thinking, "WTF is going on here?!?" Who's sending this guy PMs with "Squirt it with penetrating oil"?

Garth S

Before doing anything else, tell me if the passenger side window works - or not? If both are inop, it is the common relay ( in the passenger footwell) that is dead .... saying this assuming you have already checked the fuses ....

WallyP

One of the basics of troubleshooting is to do things in a methodical fashion. Another is to try to solve the problem in the minimum tries.

Throwing parts at a 928 problem is rarely the best idea...

To find why a window doesn't work:
- See if either window works. If not, start with the fuses and relays. When you are certain that they are good, go to the switches and check for 12 vdc on the connector 18" up the wires at the connector near the front end of the console. There are two wires between the switch and the motor. For up, one is 12 vdc, the other wire is ground. To go down, the power and ground are reversed.
- If you have 12 vdc in both directions at the connector, the problem is usually a broken wire where it goes into the door, or a problem in the motor.
- Pull the door panel, and check for 12 vdc at the motor connector. If you have power and ground there in both directions, the problem is in the motor.
- Remove the motor and take it apart. Clean and lube. Check the brushes to make sure that they move freely. There is a tiny thermal breaker inside the motor - check for continuity or power thru the breaker. You can bypass it if it is bad.

By doing things in a reasonable order, you can fix the problem in two hours, or at least find out whether you actually need a new motor.

Kore928

I've got a pass window that sometimes will not work. Drivers and sunroof work, so I ruled out the relay. What is the correct order of current? I'm thinking relay, drivers switch, pass switch then to the regulator? I checked current at my door and it's no where near 12v, plus I have another working motor, so I ruled that out.

Alan

I'd actually start with the fuse. Since you have ruled out the relay ('window regulator relay' in Porsche speak), The most common culprits for poor contacts are the switches and then the motors - but it could be a wiring connector or break in the wire too. The drivers switch is not a culprit here...

I'd pull the pass. switch and test the voltage on the back. Identify the +12 (red) & Gnd (brown) pins and then see what voltage you get between them when you operate the switch - it should not change much <<1v. If its higher - you have a problem betwen the relay & the switch.

On the other 2 terminals when operating the switch it should not be much less than the +12 terminal on one terminal and not much above the Gnd terminal voltage on the other - flipping the switch the other way should just reverse polarity. If these are good (<<1v different) the switch is OK and the issues is in the wiring to the motor - or at the motor. If these are bad the switch is the problem.

If its after the switch - check the wire connector in the front console - trace the wires from the switch - test voltage again here - same criteria. Next open up the door and test at the motor connections - it could be a break at the door hinge a stuck motor or a broken thermal cutout.

These are in the order of most likely and/or easiest to do first

Alan

JP Rodkey

My '90 passenger window quit working last week. The controller was clicking, so it looked likely to be the motor. Putting 12V directly to the motor leads got no spin, so I removed the motor from the gear housing (2 screws). Easy to see a buildup up corrosion which had gotten to the point that one of the two brushes was stuck inside it's housing and no longer making contact with the rotor.

The brush carrier should come out of the housing fairly easily, but I had to use a hammer and flat blade screwdriver to carefully persuade it along. There was rust and corrosion inside the motor housing which was cleaned out. The buildup of moisture, over time, had corroded the brush spring, which in turn deposited rust and brush dust to make a very hard deposit which caused the problems. There is a small cover that holds the brush spring in place, and the cover can be removed by carefully prying on it with a jewelers flat blade screwdriver. In my case, the brush spring immediately broke.

These Bosch motors are very common, except there are tons of variations for various performance requirements - accomplished in part by number of windings and mag wire dimension. I'm betting the nylon brush housing is the same for Porsche, BMW, MB, and others using Bosch motors. I tried to source repair parts and finally called Bosch USA for help. Surprise. All Porsche designs are officially 'NLA' by Bosch and they are prohibited from selling either the motor or any component parts.

I've got a motor on the way from an eBay auction, expecting to transfer the brush carrier over to my original motor. In the meantime, I used an ink pen spring and put everything together, which runs great. I'm concerned that the spring metal will not withstand the environment and will likely rust before an original spring would rust. When I get the 'new' motor, I'll make a final decision what to transfer or to just use the whole motor. Here are some pics for anyone interested............