What was found
MASTER CAUTION AND AUXILIARY PITOT LIGHT ILLUMINATED AT CRUISE, ALT OF 320, RT FOLLOWED NO CBS NOTED, AVOID ICING CONDITITIONS NOTE DIVERTED. ACFT GROUNDED. DIVERSION TIME - 50 MINUTES. PERFORMED PITOT PROBE SYS TEST REF AMM 30-31-00-730-801 AND AUTO AIR DATA SENSOR HEATING OPS CHECK REF AMM 30-31-00-750-801, NO FAULTS NOTED SYS OPS GOOD, NOTE: AUX PITOT PROBE WAS REPLACED ON 01/17/2016. AS A PRECAUTION R & R WINDOW, PITOT HEAT MODULE P5-9, REF AMM 30-41-41/401. REPEATED THE 2 ABOVE TESTS, NO FAULTS NOTED, SYS OPS GOOD.