MAINTENANCE BASICS 22.7.3 SLOW-BLOWING FUSES If the power supply fails, the reason for this may be that one of the slow-blowing fuses (1) has blown. Check the electrical sys- tem and replace defective fuses. 1 75_265 F3 80A: Main Power Supply / Starter F4 50A: Intake Air Heater F5 30A: Engine Stop F6 70A: not assigned 133