Found This:
Service Icon
LED will illuminate when pre-set service time is reached. When Led is On, the Preset Service time has been reached indicating that a pm is required. Refer to service manual for proper pm procedures Pre-set service time setting method - initialized by "Key On + FWD + F1 + F2", Service time display at hour meter. F1 is for upset, F2 is for down set. (with interval times of 50 hours) when the key switch is turned OFF, the pre-set service time setting is saved.
-1000 Will turn the light off permanently
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.