When the weather is warm75-85 degrees and bright sun is shining on the instrument panel when parked it occures. When I start the engine the big analog tach guage stays at 0. The digital tach reading is OK. It takes a long time before the big guage starts working as normal. This only occures in hot weather and when sun shines on dash. Any one else have this problem? And why? 
I have a 2011 RT Limited

I have a 2011 RT Limited