Had a problem with our Merc over the weekend, the battery ran flat on Friday, which is not surprising as Sandy only does 3 miles to work and back each day, driven mostly in the dark at this time of year. Jump started the car on Friday and left the engine running to charge the battery. Fine all day, not used at all Saturday. Battery dead again on Sunday morning, so decided to put the battery charger on it. Disconnected the leads to the battery, unscrewed the plugs to vent the dangerous gases and charged the battery for seven hours. Reconnected the battery to the car, switched on the ignition and warning lights appeared on the dashboard including ESP? Car started fine and all appeared normal otherwise. This morning, went to get into the car, but it would not unlock electronically, so used the emergency key to gain entry, got in, tried the key in the ignition and the car started perfectly. However no other function, lights, indicaters, guages etc worked. Warning light on the dashboard advising visit to workshop. Took car to the Mercedes Specialist, who services it regularly, expecting it to be something simple like a relay. Diagnostic checks did not indicate a fault in any area. They fitted another battery on loan, but still no change. Anybody any ideas?? It is booked in on Thursday, but the garage is puzzled by the fault. Has anyone had anything similar happen???