New Holland UCM 1512 – UCM (Universal Control Module): Right Brake Light Actuation: Short to Ground

The control module has detected that the voltage on the circuit responsible for activating the right brake light is finding a premature path to the machine's chassis (ground), which typically prevents the light from illuminating and can blow a fuse or trigger a module self-protection shutdown of that circuit.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• L313
• L315
• L318
• L320
• C227
• C232
• C234
• C237
• C238
• C245
• C327
• C332
• C338
• SR
• SV
• TR
• TV

1. 1

   Inspect the right rear tail light assembly for physical damage, cracked lenses, or water intrusion

2. 2

   Remove the right brake light bulb and check if the filament is melted across the ground post or if the socket is corroded/melted

3. 3

   Disconnect the wiring harness connector at the right tail light and check for continuity between the brake light power wire and chassis ground to isolate the short. If the short is gone when unplugged, the short is inside the tail light assembly; if it remains, the wiring harness is pinched or chafed between the rear light and the UCM.

4. 4

   Trace the right rear light wiring harness back to the UCM, looking for pinched wires near rear door hinges, engine compartment vibration points, or metal frame rub areas

5. 5

   Check the machine's fuse boxes (specifically Fuse Box #2 on EH models) for blown fuses related to the brake/tail lamps

1. 1

   Safely Prep the Machine

   Park the machine on level ground, lower the boom/attachment completely, engage the parking brake, turn off the engine, and disconnect the negative battery cable.

2. 2

   Address the Short

   If the tail light assembly is internally shorted: Unbolt the right tail light housing, disconnect the pigtail, and install a new OEM tail light assembly. If the wiring harness is chafed: Carefully slice open the protective loom at the site of the damage. Cut out the exposed/shorted section of the wire, splice in a new section of automotive-grade wire, and seal it with weather-resistant heat shrink tubing. Re-loom the harness and secure it with zip ties away from pinch points.

3. 3

   Replace Fuses

   Replace any blown fuses in the fuse panel with the exact same amperage rating.

4. 4

   Test the System

   Reconnect the battery. Turn the key to the ON position and test the brake lights.

5. 5

   Clear the Code

   Use the instrument cluster's diagnostic menu or the Electronic Service Tool (EST) to clear the UCM 1512 inactive fault code.