I have the same model as yours, a 2006 T36. Like others said, it's located in the compartment where the shore power line is located. When you look at the compartment, you'll see two 120V plugs on the top, one on each end, facing down. The left one is the block heater, the right one is for a 120V to 12V converter.
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2006 Gulf Stream Tour Master T-36
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