gearbox reverse switch in a turbo 2

[Archbish]

so I\'m trying to get the reverse switch wired in on the first gen, but without success...

I\'ve found the only likely candidate on the gearbox (there are 4 wires near the gearstick, 2 red, 2 black) that screws horizontally into top of the gearbox.  but none of these seem to have any connectivity or anything when the box is put into reverse.  So am I looking at the wrong wires, or is there something wrong with the reverse switch??

Thanks in advance,

OJ

[Prof]

That\'s the correct switch - sort of round thing that screws in.
 
I might have a spare one on my old gearbox - I think it works, but your welcome to test it.

[pdtaylor18]

Bit of a pig to check the resistance/volts as the wires are quite short at that switch but best to check you have some voltage at the bulb end first and then work your way back. Some of these switches are fragile and the wires will break off very easily due to age etc so dont bend them too much at that switch end.
On a TII you will have zero room to get a spanner on it but not sure what room you have on your setup. Its a large spanner and about a 25mm or so but mole grips will do to crack it off,they should not be that tight anyway.