Thermo King RDM II Meter is a digital hour‑meter used in refrigerated transport units to log operating hours and detect over‑run conditions. Common failure modes for this model include power supply dropout (24 V DC), internal capacitor degradation, and faulty LCD or keypad circuitry; these often manifest as blank displays, intermittent readings, or error codes such as “E01” or “E02”. First‑check diagnostic steps: verify the 24 V DC input with a multimeter, inspect the board for burnt components or loose solder joints, and review any stored error logs via the service interface. If power and visual inspection are clean, test the display and keypad continuity, then proceed to replace the CMOS battery if the time/date resets each start.[oss-gpt-20b]