2006 Mini Cooper S convertible. On sporadic occasions [sometimes even just waiting on a traffic light] all the diagnostic and fault indicators start flashing on and off. the car keeps running fine. The tachometer and speedometer may go to zero, sometimes both at once and other times one or the other. After each occasion the cruise control doesn't work and the low tire pressure indicator turns on until the ignition is turned off and back on. We may go 50 miles with no issue. Other times things will be going crazy for a few minutes. A local mechanic [not an authorized dealer] reports no diagnostic error codes on his computer and told me he thought it was being caused by a loose positive connection on the battery which he tightened charged me $200 and sent me on my way. The problem persists. Has anyone out there had similar problems? What was the fix?