28 Stepper Motor Valve Error

Thermo King Alarm Code

Description	Corrective Action
Stepper Motor Valve Error Stepper motor valve current too low or too high Indicates: Short circuit to valve Faulty stepper motor valve or circuit	Check the wiring to stepper motor valve using unit wiring diagrams and a digital multimeter. ~Disconnect stepper motor valve leads and check circuit resistance. Resistance should be 75 +/- 7.5 ohms at 24 C (75 F) between red/green and white/yellow wire leads. ~Be sure to maintain the correct polarity or valve will not work.