Thanks for the replies. The solonoid is working fine as far as I can tell; since I loosened the allen head screw it all works fine i.e. have to depress the button in selector to change gear (can't accidentally throw it into reverse at 80 klicks!

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I think the answer lies in the wires from O/D switch that run down the side of the shift lever. My shifter swiveled around a bit whilst messing around with the bulb so maybe I inadvertantly twisted the wires in the process.
BTW the bulb I was messing with was to illuminate the ashtray at night; bulb has a plastic shield on it that allows light to go out to cigarette lighter and sideways to a window into the ashtray. Is it just me or is that barely any light at all? I feel like I wasted time and caused myself more problems as a result! Ah the joys of tinkering, I'll be at again next days off!!!!
David BC
White Mystique (in need of a wash!)