First, I'm new to my 2006 Dodge 2500 Passenger Van. I've had it 5 weeks and slowly learning how it works. First tried the heater and it ran till it got hot and quit. From reading the forum figured it was the electric water pump, Replaced it and all was well. The morning it was -13 so fired up the heater to preheat the engine before trying to start it up. Heater fan comes on, runs 3-4 minutes, then shuts off. Tried it a couple of times, same thing. Would not fire up. Go back in side to warm up. Two hours later come back out, now a -5, and try it again. Now I hear the fuel pump clicking and it fires right up. So my question is, when I turn it on, should the fuel pump always be clicking? With it that cold, would the fuel pump fail? Should I replace it? It has 110,000 miles on it. As far as I can tell (Carfax) it's always been in Michigan. Thanks in advance for any suggestions or help.