Home >> Land Rover >> 2022 >> Defender 90 >> Repair and Diagnosis >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: Trailer Control Module (TRM) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: Trailer Control Module (TRM) (G2445144) >> Description And Operation >> Trailer Control Module (TRM) >> DTC B1548-23: Trailer Light Test Button - Signal stuck low >> Possible Causes