Lately the temp guage in my 2003 6.0 Express has been dropping to 0 and fast idles as if cold while driving after warmed up, then goes back to proper temp with a hesitation in engine. This only happens in the cold weather or when the a/c is on while driving on long trips.

Also, recently while driving the whole cluster went dead during a humid rainy day then powered back up after after about 3 seconds. Did not lose any other power or function.

Any help would be greatly appreciated!!!...Thanks!!!

 

Check the thermostat , rad cap , temperature sending unit.