jberks. The fan is controlled by an electronic regulator. The switch, whether digital or manual simply sends a small variable voltage to the regulator which then controls the fan speed. when they fail, these can make the fan do anything, including run flat out all the time or even speed up and slow down randomly. If your Mercedes-Benz S500’s key won’t turn, check to see if the transmission is in Park. Many models will prevent the key from turning if the car isn’t in park when turned off. Make sure your car’s parking brake is enabled before you do anything else. This should prevent the car from rolling away if the transmission lock fails (or your Try cleaning the lens on the key. It would also be a good idea to have the e.i.s. codes pulled at a dealer or equivalent. if problem persists. If the car will not start. try disconnecting the battery and wait approx. 15 min. sometimes that will give you a couple of starts unless it is just a software issue. ML320 ignition starter switch problem. I have a 2002 ML320 135K miles. To start the truck it requires a lot of pressure on the key to make the electrical contact that engages the starter. The key goes in, out, turns to the right and back easily, lights come on engine starts quickly, no problems. BUT! I bought a 1999 SLK 230 Kompressor with 62000 miles on it a month ago. first, the key sometimes was hard and needed few tries to turn in ignition untill i turned it hard and broke it. went to the dealer and got new key but before that my friend took everything apart to try to start it with those wires under steering wheel. now, the ignition . Another guy with a c class had a posted elsewhere on the forum with the same problem and a helpful forum member said it might either be that the key needs reprogramming (cheap) or the Electronic Ignition System might have to be replaced (very expensive). On my car there was a fuse (#40, labeled "fanfare) which was blown. W220 S-Class Key won't turn in 2003 S500 Help (Electronic Ignition Switch) problem and only a dealer can rectify that one. BenzWorld.org forum is one of the I have fault EZS - Electronic ignition switch ELCODE - f - 2105450308 quick report and was unable to connect via HHTWin to clear or examine further; at this time, error; com port assigned and EIS switches passive does not react to diagnosis requests in this status could not back out or cancel HHTWin and reattempt successfully after numerous Mercedes won't sell these parts to anyone they say they are security items and you have to pay the dealer to install and code the modules.(Completely illegal!) I found a company that if you send them the column and electronic ignition switch they remove the faulty solenoid and fit an emulator and program everything to work upon installation. Initially the cooling fan was coming on when the ignition switch was turned to start. Some fiddling about with the ecu and sam and copious amounts of electrical contact spray sorted the cooling fan. I am now left with the car not cranking. I have checked the starting relay and it is working as it should. The starting fuse is 20amp and is not blown.

mercedes c class ignition switch problems