My 2006 Smart Passion is showing a single bar on the speedometer again. This is the third time it's doing this. The last time I posted, it was in 2013, for the same problem. After that, I did what I could, and that is including putting my car in service with the Mercedes dealership. Couldn't find anything, but, I found something out. If I park my car in the sun (most likely in the summer), at certain temperatures, and the inside of the car gets hotter, it will not start and show me the single bar on the speedo. But if I park in the shade or in the garage for a few hours, it will start again. I've been told by one auto-wrecker that sells Mercedes parts, that it is the Sam unit that's causing the problem. My question is, if I get a used Sam unit (fuse and relay box), will I be able to program it again to work with my car? Since Mercedes dealerships won't touch it unless you buy it from them. Any help will be appreciated.