Hi guys , I spent hours to try to find a solution on why my R53 won't crank ( all of sudden ).
There are quite a few factors to take in consideration starting from clutch hall sensor to immobilizer and or starter being busted , not enough power in the battery and so on .
However I couldn't find anyone suggesting to try and check the the ignition switch .
So I decided to write this post just in case anyone will need it in the future .
The easiest way to know if you have problem with the starter or the ignition switch is to remove the cover under steering wheel and gain access to the ignition switch ( left side under the lights on/off stick)
Once you gain access to it put the car in neutral , pull the emergency break , turn the ignition key on until all the lights on the dashboard are on , press the clutch in and by using a piece of wire make a connection on the back of the switch between the red wire ( +) and black and blue wire ( starter) just touching the black and blue wire .
If the car cranks there is nothing wrong with your starter , and you need to order $90 ignition switch .

Good luck

 

I know this is all late and all, but I started having the same issue. Checked everywhere and tried the magnet trick, which only made it clear to me that it was not the clutch switch. In my case, strangely enough, was the position of my steering wheel. If it's up, it won't start. Pull it down and it starts every time, well since I figured it out, just a couple of days ago. So, I have no idea WHY this works but it does. Maybe I have a short in the steering column. Any other ideas why this works???