My first thought too, but I tried that and it didn't work unfortunately. The alarm goes off about 1 minute after locking/arming with and without the motion detector activated. Thats not to say the motion detector hasn't failed, but how randomly coincidental would that be to fail at the same time I replace the ignition switch?!

I thought perhaps I screwed up and there were two different switches, one for cars with alarms and one for those without, but RealOEM only shows one PN for "ignition switch", and I don't recall that the X5 was offered without an alarm.

There's always the chance that I broke some brittle 20 year old wire or connector when replacing the switch this am, or that I screwed up by rotatign the new switch to match the "clock" of the old one, but I can't see how the new one would have mated to the barrel that extends out and engages the switch barrel, when the key is turned. The two only mate when both are clocked correctly.

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Current
Original owner 2002 E53 X5 4.4i to 4.6i swap
2026 G80 M3 6 spd
2025 G06 X5 50e
Former
1972 Audi Fox
1986 Saab 900S
1996 BMW Z3
1998 BMW E36 M3 Sedan
2004 BMW E46 M3
2006 Audi A3 Quatro
1993 Mopar 318 Jeep Grand Cherokee
2015 V6 Jeep Grand Cherokee