'88 325is instrument cluster probs...kinda long

hi, looking for any advice anyone might have to help with this...problem started about 2 months or so ago, driving along something catches my eye n instrument cluster, look down and my speedo shuts off, the km/L thingy under the tach also stops working. Drive a bit, like throwing a switch they both start working again. This happens intermittently once maybe twice a month...may go three weeks no probs, then in one day may happen

10 times. Last night went out for short drive look down, speedo stops again, so does km/L thingy but this time my temp gauge is at 3/4 and kinda bouncing into the red....you can actually see it bouncing (it always heats up to a hair below half mark and only ever goes over half if i'm really hard on it...in summer, which i wasn't). pull over ,check things, nothing overheating, drive off. Gauge settles after about 1 mile, but still shows higher than usual. Reasearch on forums said to check si board batteries...pulled dash apart this aft and the batts tested ok...contrary to what forums said, my batts wern't 2 double AA ni-cads, but 2 half size 3v li super glued to the board(which wasn't what i picked up at radio shack lol) Anyway they were putting out 3v each so i left them put things back together, go for a drive and problem starts again. Where do i go from here? Can the something in the cluster itself be screwed(it was all connected securely,and really looked like i was first one in there)? is there any other places something coulda come loose? i can understand the speedo and maybe the km/L thingy being related...but how are they somehow connected with temp gauge? Any help greatly appreciated...thanks dave

How did you test them?

-Russ.

Look for cracked solder joint on the SI board. I simply used a soldering iron to carefully reflow all the joints and this problem went away.