the culprit is probably the SI batteries. they are behind the instrument cluster and mounted on a circuit board that is a pain in the neck to get to. they are soldered to the circuit. they need to be replaced and I recommend relocating the batteries to a more accessible location. I wired mine to the board and put them in a cheap black holder from Radio Shack and mounted it on the empty space next to my fog light switch on the dash. good luck DaveH '84 533i