i have a 1985 535i and my speedometer is doing a weird thing. when i first start to drive it works fine then about 3 mins into the drive the speedometer dies. after few minutes it picks up again and works fine usually for the duration of the drive. sometimes it won't work for 10 mintues or so but it always seems to work fine when i first start her up. also, when the speedometer doesn't work neither does the cruse controler. has anyone had a similar problem, and if so, how/how much was it to fix?