Electrical Maintenance 8-17
FUSES
Fuses (Units with TG-VI, MT µP-IV, µP-V, µP-VI, SR-2 or SR-3)
A number fuses protect various circuits and components.
The fuses are located on the relay board.
• A 40 amp fuse protects the main power circuit.
• 25 amp fuses protect the remote evaporator fan circuits on SL, TCI and SL Spectrum models; and On/Off switch circuit on
SL-400 and SL-400e models.
• 15 amp fuses protect the damper motor or solenoid; high speed solenoid; and various control relays and components.
• Several 2 or 3 amp fuses protect microprocessor circuits, control relay circuits, remote light circuits (optional) and other
components.
NOTE: Refer to the unit wiring diagram or the appropriate Controller Operation and Diagnosis Manual for additional fuse
number and size information.
Typical Relay Board – µP-VI Controller
1. K1: Fuel Solenoid Pull-in Relay
2. K2: High Speed Relay
3. K3: Damper Relay
4. K4: Preheat Relay
5. K5: Starter Relay
6. K7: Run Relay