Hall effect sensor help...

[Haylands]

Hi, Hope someone here can help me with a little problem, I'm not too bad with most vehicle electronics but I need some help with a workaround..
Brief outline...

Immobiliser system, RFID in key, insert key in ignition and the ring areal sends a signal to an electronic steering lock, this is a solenoid with a hall effect sensor inside, once the solenoid is in the fully open position the hall effect sensor sends a signal to the immobiliser to tell it that it's safe to start the car, this is a 2002-2005 Range Rover... The solenoid with hall effect sensor inside fail and you then have to buy an entire steering column at a cost of thousands of pounds...

The later Range Rovers had this solenoid removed as they realised the problems... My plan is to remove the solenoid and lock from my vehicle which is starting to show signs of the failure, it starts about 50% of the time now... I want to take it all out but replicate the output from the Hall Effect, I'm pretty sure it sends a signal when the solenoid plunger is fully locked and fully unlocked...

How do I go about measuring with a meter to see what is happening from the sensor and would there be a way to replicate these outputs to confuse the immobiliser into working...

Sorry for the lack of more detail but I'm a bit in the dark here.... If I'm asking in the wrong place could someone point me somewhere that may be able to help..??

Thanks

Pete

[David]

Wikipedia has a good informative article - search for "Hall effect sensor". If you are sure that the Hall effect sensor is faulty, it should not be too difficult to replace it. Google is the go to place here.

[Haylands]

Thanks for that, but it's not the sensor it's the design of the solenoid, it has a small donut shaped magnet inside which gets bashed everytime it activates, this, after many years, breaks the magnet which then either falls out or jams the solenoid, the failure leaves you stuck with a car that won't start... I have sourced the magnets and can repair the solenoid, the original makers can't provide new ones, they stopped making them 10 years ago... the hall effect sensor is potted inside the solenoid... I don't want to have to rely on an old repaired solenoid when miles from civilization. ( I do off road my Range Rover) I want to send a signal to the immobiliser to replicate the action of the solenoid, I'm sure it could be done but the technology to do it is way beyond me...

[David]

OK, on to plan B. Have you identified the connection to the immobiliser which allows starting on the occasions when the solenoid is working correctly? If so, put a multimeter on it and see what voltages are present when all is working correctly. That should give you a big clue - the answer may be as simple as connecting a dashboard switch to allow starting.

[Biffo]

So the solenoid operates a pin that fires into the column to lock it ? is that what you mean?

What you could try is measuring the resistance of the solenoid coil and replacing it with a suitable resistor which would fool it into thinking the solenoid is still there.

[David]

Not quite. In his post of 2/5, Haylands said he wants to send a signal to the immobiliser to replicate the action of the solenoid. He needs to post here if he has identified which wire sends the signal, and if it is a straight +12v level, or a pulse. If, for example, it is just a steady +12v, then the simple way out is to connect a supply of +12v via a switch to the relevant input on the immobiliser. Difficult to offer much more help at a distance.