BMW M52 Hall cam trigger

[lezsi]

I've tried to utilize the stock cam sensor on a BMW M52B20 engine, without success.

As I see in autodata schematic, it's a HALL sensor, feed from +12V, and have a trigger wheel with one big tooth (~50% wide) per cam rotation.

I haven't come to wire it to the VEMS unit because can't measure any signal on DVM or a scope.

When I feed the sensor with supply voltage it pulls down the output to GND forever.

Tried to pull up the output to +12V/+5V  through resistors, tried to trigger it with different steels and magnets, and tried two piece of sensors.
No luck yet. 

How these sensors should work?

[andreNL]

Fit a led from signal to ground, use 150ohm resistor in serie if its 12v reed.
Try with both sides of a magnet, unipolar senses only south side of magnet bi-polar both sides.