If you remove the instrument cluster, you'll see a little circuit board about 2" x 3" or so. it snaps off of the cluster. A lot of times you can actually see cracks or dimples around the larger solder joints on that board. Take your soldering iron and maybe just a small amount of new solder and re-flow those joints. Take care not to bridge any circuits with solder. Pop the board back onto the cluster and install it back into the truck. It should work much better.