hi Dusk just checked Haynes manual Section 7A.4 and it has the whole procedure for testing, removal and refitting the parts so is quite in depth about it...
but to answer your Question... find the cable running into the transmission, prise it out and look at it with the plastic clip at the top.
1 and 2 are Neutral contacts
3 and 4 are Reverse contacts
if you put an ohmeter between the numbered you can test if there is continuity and if they work properly...
Neutral [1*3] Reverse
contacts [2 4] contacts
(the * being the clip bit at the top)
if you want i'll scan the page and email you just give us a shout...
sory dusk just read you post properly, and i dont think my reply helps you at all... it answers what wires are for int the position switch...
i thought you meant the wires with the reverse cable... Doh
sorry