a member here said he was having issues with his gauge cluster that were caused by a loose screw on the back of the cluster.... not sure how that works but could have also just been than when the cluster was pulled out and disconnected then put back together wires that werent quite sitting right were put back into place and fixed the problem.. id take the thing apart as far as you dare (dont break anything of course!) looking for anything strange.. then put it back together and see if that helps..

as for the dealer i would ask them up front what they will do if they replace a part that doesnt need replacing... maybe a refund on the new part at very least?