Not sure if this has been covered before, but their is a simple way to test your neutral position switch.
With the engine idling and clutch depressed and in neutral, switch on the heat switch. The revs should come up to 1200ish. Now move the gear stick into each gear, one at a time. When you select a gear, the revs will drop back to idle, and back to 1200ish when in neutral. If any gear does not drop the revs, their is a problem with the neutral position switch.
With the engine idling and clutch depressed and in neutral, switch on the heat switch. The revs should come up to 1200ish. Now move the gear stick into each gear, one at a time. When you select a gear, the revs will drop back to idle, and back to 1200ish when in neutral. If any gear does not drop the revs, their is a problem with the neutral position switch.