Help! Converting headlight adjusters to electric

[Laith]

Hello all, have followed this guide http://www.e30zone.net/e30zonewiki/imag ... ters-1.pdf pretty much to the word, except the e36 adjusters I put in there are not working at all when I move the potentiometer with the lights on.

I tested the e36 adjusters by putting the live and middle pin to a car battery and the ground to a ground and they make a little motor noise then stop (I think they are stopping quickly because there is no variable voltage to it).

Is there anyone that has done this before who can help?

[Brianmoooore]

If both motors fail to work, then it suggests you've wired them both incorrectly, or your pot. isn't producing a voltage in the correct range.
There's a pot. inside each motor assembly, connected in a similar way to the adjuster pot., and the motors move their respective pots. until the voltage on their sliders matches that produced by the adjuster pot.
Disconnect the plug from one of the motors, and check, with a volt meter, that you have a variable voltage on the appropriate pin of the plug as the adjuster pot. is turned.
Much easier to use E34 motors, BTW. They fit straight on with only a minor mod.

[Laith]

I've checked the pot and it's definitely putting out a variable voltage when turned (checked with a voltmeter from the wire I've ran to the middle pin on the motors to a ground).

Thanks for the tip, the e36 managed to fit in the end I used the plastic rods instead of the old metal screws and used shims and a screw into the plastic rod.

Is the wiring of a pot correct in that guide?

[Laith]

Should I wire in the live and ground to the battery instead?

[Brianmoooore]

The earth wire from each motor and the adjuster should all go to a common earthing point, the 12 volts+ terminal of each motor and that of the adjuster should all go to a common point and be connected to a fused ignition switched live (purple/black from fuse 5 will do), and the adjustment out and in terminals should all be connected together.
From my notes, the OE adjuster pot's internal circuit is a 1000 ohm pot. with a 390 ohm resistor connected between its slider/wiper and the variable output terminal.
I also have another circuit (don't know where it came from), which shows a 4.7k ohm preset pot., with one end connected to 12 volts, its other end connected to a 10k ohm pot, with that pot's other end connected to earth, and a 330 ohm resistor from the connection between the two pots. to the output terminal.
The 4.7k ohm preset is marked 'adjust for seven volts'.
There probably ought to be a fixed resistor in the chain of two pots. as well, since if both pots. were turned to minimum, there'd be lots of smoke.

[Brianmoooore]

Just noticed that my notes FOR E34 MOTORS shows 12V+ on pin 3, earth on pin 2, and the variable voltage on pin 1.

[Laith]

Ah I see. So ignoring the fact that e36 motor pins are different do you mean something like this:

[Laith]

Essentially I need to sort out a common 12v and ground (as opposed to tapping off lights) and use a 1k pot with the 390 resistor. Would the variable voltage input in the e36 adjusters be the same as the e34 adjusters?

[Laith]

Just found this diagram halfway down the page for e36 adjusters.

http://www.m3forum.net/m3forum/showthread.php?t=425563

How do you reckon could I recreate that wiring?

[Brianmoooore]

That link gives the pin connections to the E36 motors the same as my E34 motors. Not surprising, since the actual motors and electronics appear to be the same.
The pin connections in your original link are wrong, and as a result you have connected them wrong, which is probably why they aren't working!
The wiring diagram in your latest link is the same as your hand drawn one (except for the motor connections being wrong.)

[Laith]

I see. Let's give that a go then!

[Laith]

All sorted. Pins were indeed the wrong way round! Thank you very much as always you're the font of knowledge here.

Using a 4k7 pot the adjustment is interesting, the extremes cause no movement, but if I move it carefully they work. Should I swap in a 1k pot with the 390 resistor?