I am working on what I thought would be simple project. Two weeks later, I need help.
I have a pair of vintage electric automobile mirrors to install on a Pantera. Each mirror has four wires, red, blue, and two yellows. The red and blue are + and -, and control "in" and "out". Easy to wire with a momentary rocker switch, one direction brings the mirror in, flip the switch and reverse the polarity, mirror goes out. It is then necessary to attach one yellow to red and the other to blue, which appears to lock the motor via internal coils to a different set of gears, and now the switch moves the mirror up and down. So I used another momentary switch for this function. But the switch with the yellow wires now overides the motion of the switch without the yellow wires.
I figured no big deal, just diode the yellows to control direction of the current and I'm done. Well, that does not work because the current direction reverses to reverse the motor. So I can get three directions, but not the fourth.
This is round two of this project, as I already have a nice selection of junkyard mirror control switches, all nicely diagrammed, but today's mirror use three wires for control.
Anyone have any suggestions?
George @ 410-239-3000

 

Could one of the wires be a common ground? One input to turn clockwise, one for counter clockwise, one to engage the clutch and a common ground? The BMW uses a mirror with four wires, Here is a wiring diagram that may give you some ideas:

http://www.stormpages.com/countchocula1/bmw/etm153.htm

(This is for an '85 635CSi, but applies to the 5 series also, if you think this might work I can help cross reference which cars this switch is on)

 

Thanks Chris.
I ended up using a pair of 4pdt relays with toggles which got the job done. Not the most elegant solution, but the owner wanted the switches hidden anyway.