check heater plugs and bank wiring.check the heater plugs relay.if the heater circuit fails then cold starting is almost impossible.a good sign of heater failure is engine is not difficult to start when hot.may take a bit of cranking but engine will start eventually.check that first ,replace air filter if needed then move on to the fuel system,eg filters,fuel pump..most diesels will start with a tow even when fuel pump is faulty.towing will cause the engine to overfuel and aid cold starting.
tranny granny
December 2011