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Discussion Starter · #1 ·
I am trying to understand an electrical diagram that I got from a local service department. What I am trying to do is connect a 3-wire after marker system to BMW's 4-wire system. The one thing that confuses me is the ground wire that is attached to each mirror. It looks as if the wire is attached to the mirror from two different sides (a loop?) by the looks of the diagram. If there are any electronics experts can you please tell me how to connect the 3-wire system that I have to BMW's 4 wire system?

Thanks
 

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revirD detangiseD
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What you need is the previous diagram showing the switches. Ground and power are reversed with the switch to operate the motor in opposite directions. I will see if I can print/scan it. If I'm successful I'll post.

JB
 

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Discussion Starter · #3 ·
Joe,

I appreciate you trying to post the diagram for me.

Not sure that I understand what you are trying to tell me when you say "Ground and power are reversed with the switch to operate the motor in opposite directions."

Are you saying that when I move the left/right mirror controller that the ground wire becomes the power wire and vise-versa?

Can you explain how I can correct this issue?

My guess (haven't tried) is that I need to run a wire connecting wire #4 (per diag) between the left and right side mirrors.
 

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revirD detangiseD
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Once you put the two schematics together you will see how it works. I'm at work right now, but will send you the other page when I get home.
Joe
 

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revirD detangiseD
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How it works (long)

Here's the two pages of the mirror power schematic. I'll try to explain how the power flow is for the mirror.

First off there is power all the time to the mirror heaters (if you have them). Here's how that power flows:
12 volts is present in run and start at the fuse (F24) at the top of the page. It enters the switch at terminal #2 of connector X625. This puts 12V on switch contact #0 of the third set of 1-0-4 contacts from the right. From there it is felt on contact #0 of the left most set of 2-0-3 switch contacts and exits the switch on terminal #5 of X625. This goes down to the tie point X850 and to both the driver's and passenger's mirrors entering on terminal 2 of connector X623 & X624. From there it goes through the thermal switch, the heater elements and out to ground on the brown wire on terminal 4. This causes the mirrors to be heated at all times. I'm not positive but I think the mirrors heat on at approximately 70 degrees F and off at around 140 degrees F so they are essentially on all the time. Being as there is no ground path on terminal 1 of X623 (X624) the 12V on terminal 2 does not affect the motor.

Now I'll push the switch to move the passengers side mirror up.
The three switch contacts on the right move to position #1. The middle set of 1-0-4 contacts with the switch in position 1 applies ground the motor through terminal #1 of X625 and out terminal #6 of X625, to the triangle A which goes to triangle A on the second page, which goes to terminal #1 of X624. Being as there is 12V on terminal 2 (trace it back), the motor turns the mirror up.

To move the mirror down the switch is put in position 4. If you trace it around you will see that the 12V then comes into the motor on terminal 1 of X624 and ground is placed on terminal 2 turning the motor the opposite direction, down.

I know this is a bit confusing. But it really works!:thumbup:
I hope this helps with what you are trying to do.

JoeB
 

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