Isolate the Root Cause

At this point analyze and (diagnose the problem), and develop text. Since the high beam indicator illuminated when the headlamp dimmer switch was in the high position, the high contacts of the headlamp dimmer switch and the LT GRN wire between the headlamp dimmer switch and C100 are good. At this point, it is extremely unlikely that the high beam filaments in the RH and LH headlamps are both open or that both headlamp connections are bad. The cause must be a bad connection at C100 or an open in the LT GRN wire between C100 and the RH headlamp.