Front Passenger Window motor replacement

[jsafalow]

Hello:

1983 6 series (9/82 Build) front passenger motor in operable. Checked switch for power, OK at pins... Any information on how to remove and replace window motor greatly appreciated.



Regards

[DesktopDave]

Check the window switch carefully, that's usually the flakiest part of the window circuit. They can be dismantled and rebuilt. Also check the power breaker and lockout switch for proper function.

The front window gearboxes can also strip out the spur gear. Those are quite difficult to find in good condition. Hopefully it's your switches, the window gearbox isn't a fun job.

[jsafalow]

Thank you @DesktopDave. I do have a spare switch i believe to be in good working order that I can swap. Can you advise on where are how to check function of Lockout and power breaker? For what its worth, I hear no noise from motor when pressing current switch in car. Many thanks in advance.

[DesktopDave]

Do you have the correct BMW electrical troubleshooting manual (ETM)? It's the most important tool you can have for our cars (they're all available here). It took me a little while to figure out BMW's circuit description style. Here's my short description of the window switches:

• Power comes into window switches via a red wire on terminal 3.
• Both up & down buttons have a separate ground (brown wires, terminals 4&5). The switch buttons are grounded to both "legs" (wires) of the window motor (black wire on terminal 1, blue wire on term 8).
• When you press either button on the switch, it disconnects that motor "leg" from ground, switching +12VDC to the window motor. Since the other side of the switch remains connected to ground, it completes the circuit. Clever, eh?

The '83 E24 ETM has this all on pages 52-53.

Usually, the power window switch contacts are simply worn out due to electrical arcing. BMW decided to route the full electrical load for the window motors through the switches on our cars. I think that was a poor choice, but BMW did decide on relays eventually. Here's a good link at r3vlimited for cleaning the switches (the E30 is quite similar to the late model E24). Lots of little springs and copper contacts, delicate work, but it's not impossible. I'm having the same problem with my passenger side switch as I'm typing this, LOL.

As for the circuit breaker: If you can move any of the windows at all, the window circuit breaker is set and working. If none of the windows are working, it's likely to be the window circuit breaker. The breaker switch is usually located in the center console under the stereo. It'll pop out and expose a red ring around the button to show it's broken the circuit and needs to be reset. Some cars will have the window breaker in the driver's kick panel instead (under the steering wheel, above the pedal cluster).

As for the lockout switch: The lockout switch is with the window switches in the console, it only locks out the rear window function.

[jsafalow]

Thank you @DesktopDave had to read your reply a few time through, The ETM link definitely helps, at least in understanding the terminal arrangements.

Re: Circuit breaker I can open & close driver side window with out issue. My circuit breaker is indeed on the drivers side kick panel.

Lock out switch understood now as well.

Would you recommend swapping a window switch first to check function I believe i have an extra switch?

Any insight on how to clean the existing switch/re; opening case up to get to bits inside? have contact cleaner and steel wool on hand.

Many thanks for the insight thus far.

[DesktopDave]

Definitely swap the switches to see if the problem 'follows the switch' or 'stays at the window'. I believe our late model E24 switches are the same all 'round, BMW left you three good spares, already installed.

The switch case can be [gently] opened by [gently] prying the sides of the case apart and [carefully] removing the lower connector plate. It's quite fiddly work, but not difficult to understand. These switches are not glued or sealed together. There's four little clips molded into the side of the switch case, you'll be able to see them easily. Try to keep the switch body upright, it'll keep everything together in the right orientation. I've found that cheap cell phone tools are really handy for work like this, but jeweler's screwdrivers or eyeglass repair kits will work in a pinch. It takes four hands to hold the clips open while removing the inner terminal body from the switch case.

My memory is a little foggy on these, but I believe there is a pair of tiny springs on each button contact holding the switch contacts apart. Those switch contact nubs will be worn down from electrical arcing, I'll do my best to buff them back into shape. It doesn't always work for me, but I've had pretty good luck over the years.

I've actually cracked the switch body before, but the switch block is a tight enough fit that it'll hold together anyhow. I've also made the mistake of ordering the cheap offshore knock-offs. They were quite the flop for me. It might be possible to swap the BMW switch guts into the updated case, but I haven't gotten that desperate yet.

[jsafalow]

I will give a swap of switched a try at first. Assuming that the issue is at switch if a swapped unit works I will be more than happy to try and crack open the suspect switch case and see if I can't rejuvenate the contact hubs. Hoping its the switch and not motor issue. Will update shortly. Thank you for your advice to date!

[Rdeli]

on my pre-82' e24, i had a similar issue and it ended up being the track itself. check the switches that are attached to motor, and make sure you have ground. After i checked that along w/ the switches in the middle console, i realized that the plastic hexagon retainer piece has become completely stripped (there's a little hex-head retaining bolt in the center). Behind that hexagon piece, lies the actual motor spline. I went ahead an removed that plastic hexagon entirely.

I would completely remove your motor, and clean as well. These are not hard to open up from the backside. I (carefully) sprayed some high-grade silicone grease in there around the gears, and cleaned the old grease out with a Q-tip. After that, try giving it some light taps on the back plate. I installed the motor, and gently tapped on the back while opening up the switch to make sure there was nothing stuck internally. I've had no issue since

from time to time, i have to push that motor spline back into place b/c its no longer being held in place by the plastic hexagon. Super simple fix, and way less expensive then buying a new motor. they're hard to find unused, and crazy expensive.. i want to say around $300 for single unit. You might have luck on ebay finding a used unit, but as you know that can be pretty hit/miss

good luck to you!

[RSheiman]

If you hear the motor, it may also be the old grease has locked the thing into place. I have never seen it, usually just really slows them down. Did you grab the window and try to help it down or up while pushing the switch?

[jsafalow]

Hello

Rdeli, thank you for your suggestion. I have since my last post swapped known working switch(s) into the non operating passenger window. Nothing. No noise from motor. Checked for current at wiring loom/pronged switch receptacle and receiving 12V there. My car is 83 year, (9/82 build) with the "later" interior. I will give a go to remove motor and clean/inspect hexagon piece at center spline. Do you have any insight in removing the motor from door? Is there a way to bench test the motor once out of the car?

Completely agree on motor scarcity...

Many thanks in advance.

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Hello RSheiman

No noise from motor at all. Switched to known working switch no improvement. I could give a nudge to window with a working switch...

[DesktopDave]

I'd jump the connector, since you have power at the plug. If this doesn't work, the next step is to pull the door panels and jump the motor harness directly.

If I'm reading the circuit diagram correctly, you'll need two jumper wires. In the front window switch harness plugs, the window motor wires should be black and blue, +12VDC is red, grounds are all brown. I'd whip up two short bits of wire with male spades crimped on the ends, then use them to manually connect the correct plug harness wires. I think the later model window switches used standard 1/4" ISO male spade wire connectors.

Connect one jumper from the brown wire's socket to either the black or blue wire's socket. I'd go with black. Then plug the other jumper into the red wire's socket, and use the other end to 'probe' the blue wire's socket. If the motor makes some noise, you'll know it's the switch. If no noise from the window, try reversing the polarity to see if that works.

The circuit is protected with a breaker, and our window motors use a relay to break the circuit, so you can't really cause any damage. They're a pretty crude setup, to be brutally honest...

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I've had cars with stripped splines in the gearbox. The motors will still spin, although they won't move the windows, of course. It's rare, but the wiring harness could be damaged in the door hinge. The motor could also be unplugged in the door itself, but the motor itself should always power on regardless. They're a really simple circuit.

[jsafalow]

Hello Desktop Dave:

Thank you for suggestion. I will give the jumper idea a try and report back the results. Greatly appreciate the insights.