This is on a series 2 r33 GTS, Im not entirely sure if its the same with the series one but have a look on your car anyway.
Tools:
A decent light
Flathead screwdriver
Firstly you want to find this box here:

It is right next to the steering column and it stands out like dog balls.
Pull the clip of wires out and locate the black wire with the purple stripe:

Remove the black and purple wire from the cluster.
To remove the individual wires you will have to pull out a piece of plastic that keeps the wires in with a screw driver.
Tape up the exposed lug with some duck tape and then replace the plastic inside the clip and plug back in.
Easy took me about 15 minutes. (Half an hour to sus out which wire was the door sensor)
Sorry for bad quality pics as i had to take the pics with minimum room and i have a 4.2MP camera.
If you have any questions feel free to PM me.