What was found
I/B LEFT STABILIZER DEICE LIGHT ILLUMINATED IN FLIGHT, LIGHT CAME ON TIMERS 1 AND 2 AND REMAINED ON WITH SWTICH OFF. RETURNED TO PDX. REPLACED I/B LEFT STABILIZER PRESSURE SWITCH IAW MM 30, OPS CHECKS GOOD. (S/N N122) ON, (S/N L216) OFF.