Electric Window Motor Upgrade

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kealaiki

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I recall previous discussion about upgrading the electric window motors in E9's by using the units from the rear doors of E28's, that only the rear units will work. I also remember something about switching the units, e.g. the unit from the left door of the E28 gets mounted on the right side of the E9 and vice-versa.

Can anyone confirm my recollection is correct?
 
I have heard about the rear motors and such, but I'll be finding out about this personally, as my transmissions are done for. I am going to pick up the motors, harness, relays, and switches on saturday. I'll post up what I find out.

At first glance, though, the switching sides makes sense. The e28 design has the motors on the outside of the window, when it is down. The E9 design has it the opposite way.
 
Yes, e28 rear motors are a direct bolt in. However they are NLA from any of my suppliers. Dealer may still have access to them but be prepared to pay. A window motor for a 911 will work quite nicely as well. It does not have the flat mounting flange as a e28, it will require very slight modification. I have done it, no big deal. Also 911 motors are cheap and available. Regards, Bart 8)
 
seems I heard e12 motors worked...

you should check the FAQ/tech area at the Art's coupe registry.

I roached a set of e12 motors, still have them, call me...?
 
Update:

Picked up the stuff. True to form, the motor bolts into the transmission holes, but only in the two that line up through the gear. The third is off by about a half inch. As a side note, the window only has two inputs, rather than the three of the old motor. I am attempting to figure out how to wire this thing using the old switches.

Suggestions would be welcome.
 
I have read about adapting these motors but never seen pictures, can you take some? If the motors use only two leads, they either get the ground from the chassis trough the mounting screws (unlikely), or it expects the polarity to be inverted across these leads all the way from the switch. You should consult an E28 wiring diagram to find out.

In the first case there are no changes to your switch wiring, in the second case the switch is still OK as it toggles two circuits, but you'll have to wire the ground circuit through the switches and add one wire per window between the switch and the motor.
 
I have read about adapting these motors but never seen pictures, can you take some? If the motors use only two leads, they either get the ground from the chassis trough the mounting screws (unlikely), or it expects the polarity to be inverted across these leads all the way from the switch. You should consult an E28 wiring diagram to find out.

In the first case there are no changes to your switch wiring, in the second case the switch is still OK as it toggles two circuits, but you'll have to wire the ground circuit through the switches and add one wire per window between the switch and the motor.
Click to expand...

I'll take pictures.

Based on the wiring diagrams, the switches contain the ground and direct it to change the polarity going to the motor, rather than the motor having an internal ground or a chassis ground themselves.
 
the switches contain the ground and direct it to change the polarity going to the motor

Makes sense. Your choices are to rewire the switches and run a wire from each window to the console, or if you don't want to bother with running wires you can add a relay next to the motor just to do the ground and 12V reversal. The full motor current will still going trough the switch though.
 
Suggestions on how to wire this thing?

Good pictures. I misled you, there is no need to run new wires. I assume you have to stay with the E9 4 pin switch, so here is what I would do:

The E9 switch has pins labeled 30, 31, 32, 33. Pins 30 and 31 should connect a lone wire each, and these wires go to the window motor just like they do now. Either pin 32 or 33 has a double wire which is 12V. Leave it there. The remaining pin (33 or 32 respectively) is not connected. Bring ground to that switch pin and you are done.

Make sure the switch contacts are clean (by measuring resistance between 32-31, and 30 33 withe the switch in one direction and between 32-30, and 31-33 in the other).

Looking for a GIF file of your window going up and down next...
 
Suggestions on how to wire this thing?

Good pictures. I misled you, there is no need to run new wires. I assume you have to stay with the E9 4 pin switch, so here is what I would do:

The E9 switch has pins labeled 30, 31, 32, 33. Pins 30 and 31 should connect a lone wire each, and these wires go to the window motor just like they do now. Either pin 32 or 33 has a double wire which is 12V. Leave it there. The remaining pin (33 or 32 respectively) is not connected. Bring ground to that switch pin and you are done.

Make sure the switch contacts are clean (by measuring resistance between 32-31, and 30 33 withe the switch in one direction and between 32-30, and 31-33 in the other).

Looking for a GIF file of your window going up and down next...
Click to expand...

Nope, dinnae work. The original pin configuration assumes the grouns is at the motor, rather than at the switch.
 
I believe adding the ground to the unused switch pin AND connecting two of the three motor wires to the motor should work. I forget the colors you should connect but it is the wires that are not permanently grounded.

From there on it is troubleshooting. Does the motor work if connected to the battery terminals? Do you get 12V and GND when activating the switch?
 
Did you every get this to work using the stock switch? I picked up a rear e28 window motor and was going to try the conversion.

-Kurt
72 3.0cs
 
Nope, still trying to figure it out, when I have time. The major hurdle is the E28 wiring requires the switch to control the ground. The E28 switches have 5 pins on the bottom, 2 make it go up, 2 make it go down, and one goes to power. The original motors had the ground at the motor, while the E28 ones are two pole only. I know there should be a relay or something I can place to make the old switches trip one way or the other, but wiring it not my strength.

I have tested it where the E28 motor's actions are dictated by the polarity of the input voltage. I think this is partially why the E28 motors are so much faster than the original ones, where the maximum voltage difference was 12V due to the internal ground, compared to the maximum 24V difference without it. (12-(-12)=24)

Anyway, these are the things I have noticed in my work thus far.
 
Window motor item

Looking at that pic of the window motor made a little bitty mental flashbulb go off.... those look a LOT like motors from a Benz 190, the W201 chassis. Those motors are up on ebay alla time, for small money. Wonder if they'd fit?

I've been wrenchbending for an older guy down the street, whose brother inflicted upon him a '87 MB 190. It has all the usual failings of that car: three window motors are frozen (we've unstuck two so far) and one of the regulator mechanisms is tango uniform. Trying to get a driver's door regulator - anyone? There's rust, and the paint is crap. And the AC controller is shot. But it runs okay, and Milton's a MB guy, having a 450 SEL and 420 as well. What boats, geez they drive like great big long rigid barges. Oh yeah, the fuel pump had to be replaced. And the alternator had a nasty rattle, fixed with a rebuilt unit. ENUF about them cars.
 
The E28 window motors are basicaly the same as "classic" Saab 900 motors (1981 to 1993) I should know I have a few in stock!
Check the wiring diagram for those too, they have a 2 wire feed
Malc
 
This is a great subject for a technical write up

I selfishly request if anyone has the time to do it, a technical write up. My electical experience is such that I'm lost reading this thread.

Anyway, good luck!
 
Diagram for 4 pin switch

The old 4 pin switch can still be used to operate the newer style
motors, in my opinion. Here is the before and after diagram. I haven't
tried it because I have the old motors, but I have played with the old
switches enough...

switch.jpg
 
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