Well, while you are just hanging around, why not test the glow plugs to see which ones are bad and which ones are not? I very seriously doubt all of them are no good. If none are getting power there is a fuse in the box on the right front fender that may be shot. In that box there is a plug that has the glow plug connections on it, labelled by cylinder number front of engine to back. You check the resistance from the plug socket/pin for each glow plug to ground. Depending on the plugs you have, there is a specific resistance value and tolerance. Burned out plugs register infinite resistance, and internally shorted ones have too little. But they typically fail open in short order. So, you are essentially looking for resistance values that are within a few tenths of an Ohm (I believe mine are around 1.8 Ohms) of each other, in the low single Ohm numbers. Only bad ones need to be replaced.

The other issue is fuel. I believe your car has a pump on the front side of the injection pump that is for hand priming the system. You unscrew the knurled (actually too nice a description - it has some rough, sharp cut grooves designed by some S&M Nazi that will peel the skin off your fingers while pumping the pump) top, and then lift it up and push it down a few hundred times or until you hear a sort of "buzzing" noise on the downstroke and feel some resistance. Once the system is primed you push the plunger down and screw the top back down finger tight, and then you can try to start it. Without fuel, glow plugs are pointless. And once you get fuel in there, you have to make sure there are no air leaks. So, once it starts let it run while you look for leaks.

Other items that affect the ability to start are valve adjustments, and the viscosity of the oil. As it gets colder these features can play a bigger role. You need all the heat of compression you can get in cold weather, and valves that close at the wrong time preclude generating the highest compression and temperatures. Overly thick oil also places a significant extra load on the starter, which slows the speed of the engine down. And, when the engine slows down the cold block acts as a heat sink, lowering the air temperature in the combustion chamber.

So, while you are waiting around, you can be addressing some of the items. That fuse is a few cents compared to the $60 glow plugs and if you have been energizing the glow plugs a lot, it seems likely that if none are working now that the fuse and not the glow plugs themselves are at fault.

Keep us posted and good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)