tach not working

[bmws50b30]

i have a VDO cluster from a 325i. my tachometer just stopped working. if it's the SI batteries, would my temp and mpg work? i am assuming my batteries are good since only the tach is not working. all fuses are good and the grounds are good as well. on rare occasions it would work for a second while driving then dies out.

what else can i do to fix my tach? thanks.

[mooseheadm5]

Take it apart and touch up every cracked solder joint on the board, paying particular attention to the solder joints for the plugs at the back and at the tach. At this time, inspect the SI board for bad solder joints and leaking batteries.

[twright]

I fixed the Tach on my 1991 318is by tightening the nut on the tach motor that drives the needle. This is not the nut on the back of the cluster. You have to take off the back of the cluster to get to this nut, but it is an easy fix.

[bmws50b30]

thanks! i will try both