So it's possible its still a broken signal wire in the instrument cluster?
The broken solder joints are a complete pig to see at times, if it's not clear in your view you might not be able to see it at all.
When I re-soldered my instrument cluster I had to get the thing just at the right angle and get the light on it to be able to identify the broken solder joint.
I agree completely, so maybe the OP needs to get his instrument cluster tested, unless he can give it a very good examination and try to reflow any suspect connections.