Hopefully someone with more experience will chime in, but these cars seem to be very sensitive to plugging/unplugging things with the battery still connected. I guess it has to do with things not being in "sleep" mode yet?

Can't hurt to do a battery reset overnight... definitely worth a shot. Hopefully it's not something you have to re-engage in programming. Were you using a regular bosch 5 pin style relay? Terminator suggested a normal 30A or 40A auto relay would pull too much current and cause a problem...

After seeing your response above I went searching and made up a circuit to do a switched micro-style relay (the one Term suggested) in a project box. Going to hook it up tonight. Will report back as to if I am in the same boat as you or if it works...

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
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