Fancy Aftermarket Truck Mirrors

[Dumpsterholic]

Hi all.

I just scored a pair of heavy-duty truck side mirrors which at one time were sold to people who owned Ford F-150 or Dodge Ram pickup trucks. They were made by a company called Schefenacker, now apparently in reorganization... Not that I particularly care, because I paid $7 at a thrift store for a left-right pair that used to sell for $350!

What I DO care about is how to put these puppies to work. From what I have gleaned on the Internet, each mirror assembly contains an adjustment motor and (perhaps) a heating element for de-fogging or de-icing. On each unit, five wires terminate in an automotive-style connector, and these appear to be separated into a bundle of two and another bundle of three. My question is this:

I'm guessing that two wires go to the heating element, and that the remaining three are the ones I need to energize in order to move the mirror. Obviously, a DC motor needs only two leads, and in a setup like this, side-to-side motion could be effected simply by switching the polarity of the current through the motor. Does this imply that my units are also capable of up/down motion, and if so, how do these three (or five) wires interact? If there were only two wires total, I would just hook up a 12VDC power supply and toggle the polarity, but this five-wire setup has me stumped. Owing to the pristine condition of these mirror assemblies, I'm a little reluctant to tear them apart just yet.

OTOH, if any of you owns a big pickup and would like to offer me something in trade for these hefty units, make a note here. I already have plenty of motors, linear actuators and other parts in my junk box, so it might be wise to not tamper with the mirrors at all. I can post pics if anybody is interested; one part number I found on the right-hand unit is #1406966 RH, and presumably the left-hand unit has a similar number.

[CatalinaWOW]

Don't know how Ford does it, but suspect it is very similar to my GM.  Attached schematic shows how it is done.

[drussell]

The two wires that are not direction motor are probably either heating, which is usually fairly obviously going to some kind of heat tape or element on the back of the glass, usually spiralled around and visually obvious, or are one of those auto-dimming mirror features using an LCD polarizer activated by the 12V unless there is some obvious turn signal or courtesy light or something else on the unit.

[Dumpsterholic]

CatalinaWOW and drussell:

Thanks for your input. I had already looked elsewhere on the Internet for information, but what I got failed to explain my five-wire setup.  I had tested all five wires for continuity and resistance, and the results left me puzzled, because some combinations of wires gave me a resistance reading that jumped up, then down, leading me to suspect some kind of capacitor inside the housing.

My rule about salvaged electronic devices is to verify that they're in working order before I tear them apart. These are sealed units which I couldn't find a way to open up without causing irreparable damage, but after reading your posts I forged ahead, systematically applying 12 volts DC to each combination of wires with first one polarity, then the other.

The result was my discovery that, just as I had suspected, there are indeed two motors, one for left/right and the other for up/down adjustment, plus two wires that may connect to some kind of heating element, though I didn't bother to verify that by waiting for it to warm up.