Hi my 1989 240dl saloon has a problem with the dash warning lights,eg alternator,oil,brakes etc ,they come on after starting very dimmly switch on and off the engine they can stop workin alto gether apart from oil and handbrake light,i have checked all earths i can find and connections,ocasionally the rev counter fluctuates anand the engine revs go up at idle ,this faults comes ands goes ,withalarming regularity ,any ideas.