CONTROL HARNESS "C" MERCEDES Upgrade your aftermarket head unit whilst maintaining use of your factory steering wheel controls. Require secondary harness and patch lead to complete installation. Suits Mercedes A-Class W169, B-Class W245, C-Class W203, CLC 2008-2011 CL203, CLK 2005-2008, M-Class W164, SL 2002-2011 R230, SLK R171 2004-2011, Sprinter 2007-, Viano 2008-2011 and Vito W639. Compatible with Quadlock Audio 20 system. This Aerpro control harness allows you to upgrade to an aftermarket head unit whilst maintaining use of your factory steering wheel controls. Steering controls are considered a primary harness and will require a secondary harness and patch lead to be used in conjunction for plug and play. Features Plug and play Retains the factory Steering wheel controls Phone button compatibility: Yes (when enabled from factory) Patch lead: Type C Notes: Compatible with Audio 20 units, Not compatible with factory amplified systems, Track back and forward buttons will only function when "Audio" is selected on the MFD Reverse (Purple/Violet) Handbrake (Light Green) VSS (Pink) Telephone Mute (Yellow/Black)