What year 190D, how many miles on it?
What year 190D, how many miles on it? Replace your glow plugs if they are over fourteen months old. Check the glow plug wire harness for damage, it is cheap to buy a new one if needed. If it is a W123 or W124 body style, follow the glow plug wires to the relay, remove the relay cover, check the fuse strip for cracks, and replace as needed, some of the early ones had a roughly 1.5 inch square fuse strip block on the driver inner fender. In weather that cold, you should use synthetic 0W40 engine oil, it will improve starting. Replace your fuel filters if they are over fourteen months old. Have the battery, alternator and starter tested. Some links to help: electrical problems or gremlins http://www.mercedesshop.com/shopforum/showthread.php3?p=813923#post813923 Glo Plug Testing?
