Electrical Maintenance 8-8
SMART FETS
A Smart FET (Field Effect Transistor) is a circuit control device that acts like a relay and a circuit breaker. Smart FETs halt
current flow if an overcurrent condition exists, and resume normal operation when current flow is within limits. Smart FETs are
not field repairable. Refer to the appropriate Microprocessor Diagnostic Manual for more information about the Smart FETs.
SMART REEFER 2/3 (SR-2/3) MICROPROCESSOR CONTROLLER
Refer to the Truck SR-2 Single Temp Diagnostic Manual TK 54292/TK 55208 for complete service information about the
Microprocessor Controller and the related components.
LED 20 (Not Used)
LED 21
Status – Flashes once per second when the base controller is powered and operating normally.
Flashes several times per second when flash loading. Is on without flashing during reboot and when
under test. Flashes twice within 1 second followed by 1 second off if a CAN communication error
is present.
LED 22 K8 Drain Tube Heaters Remote Evaporator (Not Used)
LED 23 K9 On/Off Circuit
LED 24 K6 Fuel Solenoid Pull-In Circuit
LED 25 K7 Starter Circuit
LED 26 (Not Used)
LED 27 ETV*
LED 28 ETV*
LED 29 ETV*
LED 30 ETV*
* May be illuminated even if the ETV outputs are not used.
Interface Board Outputs With Smart FETs
Output Function
Run Relay Coil
High Speed Relay Coil
EVA, EVB, EVC, EVD ETV Outputs
CIS Condenser Inlet Solenoid
HG Hot Gas Solenoid
PV Purge Valve
LIQ Liquid Injection Solenoid
EXC Alternator Excite
ALPC Alarm Light (Optional)
ALM Alarm Light (Optional)
Interface Board LED Functions (Continued)
LED # Function
To Next Page
Loading...
Need help?
General
