If I remember rightly although some Chrysler gearboxes had a combined inhibit and reversing light switch on the gearbox, the inhibit switch on the 410 is at the base of the gear selector with a single function reversing light switch mounted on the gearbox. This would make more sense of the car starting in some gears and not others.
With any luck I have managed to attach a picture of the inhibit switch mounted on the gear selector on a 410
http://www.bristolcars.info/forums/a...1&d=1711878008