Hi there hope i can be of assistance.
Ok there are a couple of common failures that can cause this.
One is the instrument pack itself. The internal circuitry simply burns out causing poor contacts which means a replacement is needed.
the other one, which you can check yourself is a loose multiplug. This is located in the passenger footwell, at the bottom of the A pillar. You will have to remove the triangular piece of trim to expose this (kick plate).
You will see lots of wires running in and out of a black plastic block with a 10mm bolt running through the middle of it. Check this is tight. Often these come lose over time causing all sorts of problems with the dash ans exterior lights etc.