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The Fan is inside the furnace. It's all a self-contained unit. There are several documents for the furnace in the FRF library. Here's a link to the trouble-shooting guide to get you started. http://www.forestriverforums.com/for...do=file&id=119
I image the power to the furnace is connected thru a plug so the first thing to do is to unplug it at the furnace to see if the short is in the wires leading to the furnace or in the furnace itself. Good luck!