One of my motors locked up. It had been working but froze. Luckily the arm was in a position where I could get the frame and motor out of the door.
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A few tips on installing e28 window motors
- Thread starter jmackro
- Start date
JMackro's setup has additional relays to shift the heavy current load away from the switches. Looking at the wiring diagram for '74s and the Prospero color diagram for 73-74, it shows "Load Shed Relay for Window Lift"... It looks like BMW took this step in later models? The " Automatic cut-outs" in the circuit are the circuit breakers under the steering column?
[EDIT} I misread the drawing, motor still gets power direct through the switch.
If this is wired into '74s, where are the Load Shed relays located? Under the dash near the steering column?
[EDIT} I misread the drawing, motor still gets power direct through the switch.
If this is wired into '74s, where are the Load Shed relays located? Under the dash near the steering column?
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Thanks Chris! Very helpful. I created one something like this for myself for the '02.
I misspoke/misread the diagram. Even on those diagrams the motor still gets power directly through the switch. Which leaves me wondering what the Load Shedding Relays do?
I see that the direct battery power is allowed to pass through the relays to the motor circuit breakers when the ignition is in On position, but what is the "load shedding"?
Edit by Moderator: these are actually latching relays which are activated when the key is on or when the driver door is opened in 73s that have the circuit breakers
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I thought I had seen some additional wiring information on the SPDT relays. Is there additional information how to wire these up? Have the motors and just bought the relays. Time to make this happen!! (My drivers side window is now stuck in the up position)
Gordon, been gone most of weekend.
Yes, there are some updated drawings.
I have a Georgia Tech friend named Ed, that is a race team engineer. He builds wiring systems for race cars. He gave me lessons in how to do it right. He also owns and does my dyno tuning of my highly modified 88 M5.
Hopefully this will help you. NO soldering please. Ed's pet peeve.
Perfect, thanks
Did your friend give a type/current rating for the diodes? 1N4005, or something beefier?
Thanks!
Does anyone know if E24 / 635 window motors will work the same as the E28 motors for rear window E9 conversion?
My rear windows are intermittent, and might as well address it while rear panels are off.
BTW, thanks for the wealth of information in the many E9 Coupe Forum posts on the subject!
My rear windows are intermittent, and might as well address it while rear panels are off.
BTW, thanks for the wealth of information in the many E9 Coupe Forum posts on the subject!
E28 motors from the rear doors work on front and rear coupe windows. If they worked it would be all over this Forum.
Here is another take on using Porsche motors:
e9coupe.com
Window regulator & motor advice
Hello, I have a '72 3.0CS and have some questions regarding the front window regulators and motors - for now. I have been researching the forum and see that many folks have done the e28 rear window motor conversion. Looks like a nice upgrade. My car has the sardine can style motors. My...
e9coupe.com
OK, Thank You! Chris!
My son has a donor E24 so it was worth a shot.
I have Porsche motors. I'll start counting teeth. Looks like 8 works.
My son has a donor E24 so it was worth a shot.
I have Porsche motors. I'll start counting teeth. Looks like 8 works.
ATL_Alan
Well-Known Member
Hi Chris,
Do you need the "Two SPDT relays per motor" in a 74 with non-sardine can motors?
Thanks, Alan
I don’t think relays are needed but others with more experience believe they help.
Baikal Bimmer
Well-Known Member
I had a question about the use of the diode in the diagram provided by m5bb. If I don’t use one will the system short out? It seems that way because the diagram appears to show pins 87a 86 and 30 of both relays all connect together, the only thing that would be stopping positive coming in contact with the ground would be the diode?
As you can tell I have no idea what i am doing
Any help is appreciated!
As you can tell I have no idea what i am doing
Any help is appreciated!
Baikal Bimmer
Well-Known Member
Is there some other way to wire these up without the diodes, or I am making an issue where the isn’t one?I had a question about the use of the diode in the diagram provided by m5bb. If I don’t use one will the system short out? It seems that way because the diagram appears to show pins 87a 86 and 30 of both relays all connect together, the only thing that would be stopping positive coming in contact with the ground would be the diode?
As you can tell I have no idea what i am doing
Any help is appreciated!
I too am confused by that diagram, why would 87a even be connected? And why ground back to power? Perhaps for the early sardine can relays? Also, convention should show power in from 30, not out, although they will work with 30 or 87.
i am curious why you wouldn't just use a 4 prong relay with 30, 85, 86 + 87 contacts. if you left off the 87a wire, it should work like a 4 prong relay
i was just looking up the same thing about power coming in at 30 and out at 87. 85 + 86 ... seem backwards to me as well. the power to activate the relay should come from the switch to activate 86 ... converting to ground at 85. i am just familiar with the sardine can motors and putting a relay in to avoid running all of the power thru the switch. i know the e28 motors are different.
as i remember if power comes down the green wire, it comes from the switch to activate the up side of the switch. if power comes down the black side, the switch as activated the down side of the switch. to me, both of those should come into 86 to trigger the relay - which would then divert power from 30 to 87. at least this is what i have seen with most BMW wiring diagrams ... unless i just have this all wrong.
i was just looking up the same thing about power coming in at 30 and out at 87. 85 + 86 ... seem backwards to me as well. the power to activate the relay should come from the switch to activate 86 ... converting to ground at 85. i am just familiar with the sardine can motors and putting a relay in to avoid running all of the power thru the switch. i know the e28 motors are different.
as i remember if power comes down the green wire, it comes from the switch to activate the up side of the switch. if power comes down the black side, the switch as activated the down side of the switch. to me, both of those should come into 86 to trigger the relay - which would then divert power from 30 to 87. at least this is what i have seen with most BMW wiring diagrams ... unless i just have this all wrong.
Baikal Bimmer
Well-Known Member
I have become very confused, I am going to need someone to spell it out, like I know nothing about relays or wiring…. Which I don’t