This unit must be programmed after installation using a diagnostic tool by following the on-screen instructions.If the vehicle has an existing error code, use the diagnostic tool to clear it during installation.Once the error code is cleared, the unit will function normally.If the error code persists, disable the trailer module setting, as the error may occur when the trailer module switch is activated.Disabling this setting should resolve the issue and allow normal. The unit includes a control module designed for use with both trailers and tractors, making it suitable for applications involving either type of vehicle. OEM part numbers: 164 900 54 01, 164 440 35 01, 164 440 46 01, 164 440 54 01, 1649005401, 1644403501, 1644404601, 1644405401, A 164 900 54 01, A 164 440 35 01, A 164 440 46 01, A1649005401, A1644403501, A1644404601, A1644405401, 164 540 01 01, 164 540 11 01, 164 540 22 01, 164 540 72 45, 1645400101, 1645401101, 1645402201, 1645407245, A 164 540 01 01, A 164 540 11 01, A 164 540 22 01, A1645400101, A1645401101, A1645402201, A1645407245, 164 540 73 45, 164 540 74 45, 164 540 75 45, 164 540 78 45, 1645407345, 1645407445, 1645407545, 1645407845, A 164 540 73 45, A 164 540 74 45, A 164 540 75 45, A1645407345, A1645407445, A1645407545, A1645407845, 164 540 79 45, 164 540 81 45, 164 540 84 62, 164 540 88 45, 1645407945, 1645408145, 1645408462, 1645408845, A 164 540 79 45, A 164 540 81 45, A 164 540 84 62, A1645407945, A1645408145, A1645408462, A1645408845, 164 540 89 45, 164 540 90 45, 164 540 91 62, 164 540 92 45, 1645408945, 1645409045, 1645409162, 1645409245, A 164 540 89 45, A 164 540 90 45, A 164 540 91 62, A1645408945, A1645409045, A1645409162, A1645409245, 164 900 48 00, 164 900 54 01 80, 164 900 72 00, 1649004800, 164900540180, 1649007200, A 164 900 48 00, A 164 900 54 01 80, A 164 900 72 00, A1649004800, A164900540180, A1649007200, A 164 440 54 01, A 164 540 72 45, A 164 540 78 45, A 164 540 88 45, A 164 540 92 45 Compatible models: /8 W115 200 D 1968/01–1977/01 GL-Class X164 GL 320 4MATIC 2006/09–2009/05 GL-Class X164 GL 320 /350 BlueTEC 4MATIC 2009/12–2012/08 GL-Class X164 GL 350 4MATIC 2010/10–2012/08 GL-Class X164 GL 420 4MATIC 2006/09–2009/05 GL-Class X164 GL 450 4MATIC 2006/09–2012/08 GL-Class X164 GL 500 4MATIC 2006/09–2012/12 M-Class W164 ML 280 4MATIC 2005/07–2009/07 M-Class W164 ML 300 4MATIC 2009/07–2011/12 M-Class W164 ML 320 4MATIC 2005/07–2009/07 M-Class W164 ML 350 4MATIC 2005/02–2011/12 M-Class W164 ML 350 4MATIC 2009/07–2011/12 M-Class W164 ML 420 4MATIC 2006/02–2009/09 M-Class W164 ML 450 4MATIC 2009/09–2011/12 M-Class W164 ML 500 4MATIC 2005/07–2011/12 M-Class W164 ML 63 AMG 4MATIC 2006/01–2011/12 Not compatible with vehicles equipped with (Code 848) Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.