FLYVMO

After reading a ton of previous posts on the '87-up headlight motor and wire/pin arrangements, I am now completely stumped. Today I was wiring my 90 headlight motor (motor connector damaged)to the InfinityBox electrical system. So I am putting on a new connector and...

As I took a part what was left of the headlight motor connector I noticed that the wire colors and pin arrangement does NOT match the shop manual. Hopefully our electron experts can shed some light on this conundrum for me. Here is what I know (not a lot..but bear with me):

Pin color layout on CAR SIDE CONNECTOR is, as per WSM:
Pin 1 - Red/Black (power motor one way)
Pin 2 - Brown/Red
Pin 3 - White/Black
Pin 4 - Brown (ground MP1)
Pin 5 - Blue/Black (power motor other way)

Now, this is the pin/color layout on the MOTOR SIDE CONNECTOR, in reality:
Pin 1 - Black
Pin 2 - Brown
Pin 3 - Blue/Black
Pin 4 - Red/Black
Pin 5 -Grey

WTF over?? Is the pin numbers on the CAR CONNECTOR SIDE not the same as on the MOTOR CONNECTOR SIDE? Or did Hanz and Franz decide to make this a "special headlight motor"?

I understand there is a diode in there somewhere and I don't want to damage the motor, so how would I go about testing to find out which the REAL power connectors (up/down) are? All the wires are the same gauge on the headlight motor side so I can't even distinguish them by size difference. On the car side connector the should be different sizes, but as I have no car side connector or harness, I can't cheat that way.

Picture below of the headlight motor wires.

Cheers!
Carl

Alan

The Wiring diagrams don't tell you the colors on the motor side only on the car side.

There are no diodes in the motor after 1986.

Brown clearly goes to pin4 and it is for the switch.

Assumption would be Red/Black = Red/Black
Assumption would be Black/Blue = Black

Test these two these by seeing what ohms you get across these (on 1x)

Assumption would be that White/Black & Brown/Red Map to Blue & Grey (one way or the other)

See which of these connects to ground (~0 ohms) and which is OC to ground.

Assuming the motor was parked when removed (and assuming it hasn't been messed with) the one that connects is equiv to the White/Black

Alan

FLYVMO

Thank you Alan,

I went out this morning and tested the connections. Between the following pairs I get:

Red/Black and Black = 0 ohm
Brown and Blue/Black = 0 ohm
Brown and Grey = 0 ohm

I am fairly certain that the motor is not in the parked position, (curious kids that turned the ****) but I am not too concerned with the position of the "sensing circuit" at the moment.

However, for the power (up/down) connections, is 0 ohm normal on the motor side? I have a bench top power supply (limited to 5 A). Does this have enough power to move the motor to confirm/test the motor and direction, or is there a better way, like directly to a battery?

Cheers!
Carl

FLYVMO

Going on the assumption that the WSM pins are correct and pin 1 and 5 are the power connections for the motor, (and the motor colors are totally mixed up) I tested the equivalent locations on the motor side, on the grey (5) and Black (1), and I get 46.7 ohm. Does that sound like a correct measurement?

Cheers!
Carl

Alan

OK this seems odd - 47 ohms is far too high for the motor which I'm sure will consume >7A (at least at start-up).

You were on ohms 1x mode right? not continuity tester mode? (many meters give erroneous ohms results in that mode). Also check that the DMM meter battery is OK.

I'd expect the motor to be well <2 ohms. Your 5A supply may not be able to handle it (unless it has current limitation).

If you can run the supply in max 5A current limited mode - then that should likely be enough to rotate the unloaded motor. It will go to its park position - for the direction you are driving it. If you reverse motor polarity it will go to the other park position. In all but the park positions the brown and the 2 switch wire will be connected together - one or other of the switch connectors will go OC only in the park position for its direction. Seems like that is what you are reporting - both connecting - try rotating the motor and see what changes.

BTW your initial assumptions about the motor connector are wrong:

Pin 1 - Red/Black (power motor one way)
Pin 5 - Blue/Black (power motor other way)

These are not referenced to the ground - they simply go to the motor connections:

When Pin1 is 12v and Pin5 is 0v the motor turns one way
When Pin1 is 0v and Pin5 is 12v the motor turns the other way

When Pin1 & Pin5 are at the same potential nothing happens. No current flows to the (brown) ground wire in the motor connector when the motor runs.

So assume the connector location are correct - but recheck those ohms - something is way off.

Alan

FLYVMO

Good morning Alan,

I was in Ohms mode, both in "Auto", and then manually set the range, no difference. Battery is 2-3 weeks old (last replaced), I will replace with another one and re-check.

I realized after your reply that I did not have the ground (brown wire on motor) grounded to the chassis and just checked the two power wires. I will re-check this morning.

The reason I assumed what I did regarding the power up/down wires was the following. On the remnants of the motor electrical connector, I can read numbers 1 through 7 (6 and 7 not used) embossed on the rubber. On this connector, #1 is black, #2 is brown, #3 is Blue/Black, #4 is Red/Black and #5 is grey. I deducted (erroneously perhaps) that the position numbers would correspond to the same positions on a car-side connector (which I don't have).

Am I correct in my understanding that the electrical motor and "position sensing disc" are separate units within the motor, in other words, no electrical connection between the two?

The final controlling unit for this motor will be an InMotion controller (part of the multiplexing electrical system) which has current sensing capability, and stops the motor once it senses it is up/down based on increased current draw. It also "learns" the typical current draw of a device and stops if outside of that learned current range. So I am not using the 928 headlight relay and associated wiring to the "position sensing disc". I just need to verify that I have the power connections to the electrical motor correct.

I will re-test with the brown wire grounded to chassis and check Ohms again as you prescribed earlier.

Cheers!
Carl

FLYVMO

Re-measured, new battery in the instrument.

Only wire combination pair that gives me a resistance other than 0 is between Black and Grey wires.
Brown wire is connected to chassis ground. Initially 55 ohms this time. When manually turning the headlight motor with the **** on top, reading goes to 0, then when I stop turning, the Ohm reading changes to 16 ohms, turn some more, back to 0 Ohm, stop turning, Ohm reading at 5.5 ohm etc.

So this leads me to believe that the Black and Grey wires on the motor are the actual motor drive connections. That also matches the pin numbers on the motor electrical connector remains. Next is to apply power to these two pairs and see if the motor turns.

Cheers!
Carl

FLYVMO

OK, it is confirmed. With a bench top power supply, power applied to the black wire turns the motor counter-clockwise, facing the driver's side, looking straight at the motor. Applying power to the Grey wire moves the motor clock-wise. Actually only took 0.7 A to turn it at 12.8 V. No headlights mounted, so motor did not need to lift any heavy items.

So, the wire colors on the motor side DO NOT match the wire colors on the car side harness, in case someone else has a broken connector. So pins #1 and #5 (on motor) are for powering the motor as per the WSM (colors just different on motor), and pins # 2,#3 and #4 are for the position sensing disc. I haven't deciphered which is which yet of those remaining wires.

On this 90GT headlight motor (YMMV), the connections are:
#1 Black (turn motor counter-clockwise)
#2 Brown
#3 Blue/Black
#4 Red/Black
#5 Grey (turn motor clock-wise)

Thank you Alan for all the helpful tips and your time. It is, as always, extremely appreciated.

Cheers!
Carl