RV Repair: Rv Furnace, time delay relay, fuse panel

Question
QUESTION: Should there always be power going to the furnace? I have 4 wires that come into the furnace. 2 are obviously the thermostat wires, and I am assuming the other 2 to be power? One is black, the other white. I know what the say about assuming, but I do it nonetheless. I have put a voltmeter on the black and white wires and get no reading. I have no heat at all. I recently aquired the travel trailer and was told the heat was never used. Any help you could give me would be greatly appreciated. The unit is a Suburban model NT35K. Thanks again

ANSWER: Yes. The black is   and the white is -. The t stat wires are blue I think? You should have 12 volt to the black and one of the two t stat wires should also have 12 volt. Ground the meter to the LP line or the side of the furnace. If still no power then you will have to find the fuse panel. Let me know.

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QUESTION: Ok I have power to both spots. I turn up the thermostat and get nothing. The fan wheel doesnt spin, no igntion, nada. Next step is? Thanks again..

Answer
Remove the T stat from the wall, and remove the to wires at the back. strip them and twist them together. If furnace kicks on after a few minuets then replace the T stat. If still no operation then we will need to look at the Time-delay Relay. Good Luck. Let Me know.