Proper connection of a non-BMW provided GPS receiver to specific BMW plug

[colirv]

I did exactly what you did. I used this lead. I imagine you used something similar. My setup has been in constant use for nearly a year in all weathers without problems. FWIW, on turning off the ignition the XT's shut-down procedure is delayed, as expected. If your XT has recently stopped charging through the cable I suggest you look for a poor connection first of all.