Hi all. I hope someone can answer my query and please bear with me - female who knows nothing about cars but is learning fast! I have a 1986 420SL which is ticking over at 3000rpm. The ABS light is also on. My mechanic thinks it is a faulty relay unit (?) under the dash. He reckons its the same unit that controls the ABS and has ordered a new one from Mercedes. I feel that he's not very sure. Does anyone have any experience of this fault? I'm very frustrated - my car has beein the garage for over a month getting all the bodywork seen to - she is looking fab but I still can't drive her!