Looked at a Mercedes E211 today for electric boot release inop.Customer said he knew the problem (googlepubdiagnostics)and supplied a new latch assy that he had purchased.I thought I just give the car a quick check only to find that the number plate lights did not work either (not mentioned by cust).So I guessed there would be broken wires up the boot hinge.Seen it before,main earth wire broken.So I fitted the latch and told the cust that this had not fixed the fault and did he want me to investigate the problem further.He agreed ,I repaired the wiring and all good.So the customer has now paid for a lock,fitting and my time to check and repair the original fault.Don't you just love these customers?Long may it continue