Seat position sensors, range rover

[GnilojCHERV]

Hello, I am working on a project regarding the ECU in the Range Rover 1993. I am trying to measure the value of seat position sensors, I tried measuring the resistance while moving the seats but it doesnt show me the value consistently, most of the time it shows nothing. I am sure I am missing something, maybe you know what kind of sensors are used in this kind of application, or what I should try measuring? I attached the diagram for the sensors.

 

[wwfeldman]

measuring resistance is best done with nothing else in the circuit

when you measure the resistance while the resistor is in a circuit,
you aren't getting the resistor, you're getting the resistor and
whatever is in parallel with the resistor

since you don't know what else is in parallel, you won't get good values.

your meter injects some voltage and measures the current draw.
to get resistance. said voltage may be enough to turn on any active components in a parallel circuit, thereby NOT yielding the resistance

if the schematic you posted is correct, you might try putting the seat in
the most forward position, disconcerting the sensors form the processor, and measuring the resistance
then reconnect, move the seat a known amount, and repeat the disconnect and measure
repeat until you get to the furthest back position
graph position against resistance.

 

[GnilojCHERV]

measuring resistance is best done with nothing else in the circuit

when you measure the resistance while the resistor is in a circuit,
you aren't getting the resistor, you're getting the resistor and
whatever is in parallel with the resistor

since you don't know what else is in parallel, you won't get good values.

your meter injects some voltage and measures the current draw.
to get resistance. said voltage may be enough to turn on any active components in a parallel circuit, thereby NOT yielding the resistance

if the schematic you posted is correct, you might try putting the seat in
the most forward position, disconcerting the sensors form the processor, and measuring the resistance
then reconnect, move the seat a known amount, and repeat the disconnect and measure
repeat until you get to the furthest back position
graph position against resistance.

Thank you! This makes sense, I will try to measure it this way.