It seems like I can "re-boot" my 4Matic when the light comes on by disconnecting the neg. battery cable. Why can't you do the same thing by turning the system off with the 4Matic "test" switch in the engine compartment? I don't have a wiring diagram and would like to know if the "test" switch is a simple on/off or something more sophisticated. The 4Matic works fine when the light is off but the light will come on for no apparent reason. Thanks, srharvey
'82 380 SL, 150,000
'83 240D, 250,000
'93 300TE 4Matic 315,000
'04 Lexus