can someone confirm that the blue wire is the "C wire"? What are the other wires (yellow, light pink, brown, and orange) that are not connected to anything?

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    what does the other end of the blue wire connect to? .... other wires are for future expansion and for redundancy in case there is a problem with one of the other wires – jsotola Jan 12 '18 at 0:17
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    Is this how the current thermostat is connected and works as expected? Best answer is to look at the other side of the wire on the furnace controller side and see what each wire is connected to (if at all). – noybman Jan 12 '18 at 2:30

R and C are your power wires. W is for heat and G is for fan. Cables come with multiple wires in the bundle. The rest are just extra for future use like if you added air conditioning you would use the yellow wire usually. Orange if you were to add a heat pump and so on. Or if one of the wires were to break you could use one of the other ones.

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From the information you provided, it's not possible to determine if blue is actually your C wire.

Does your thermostat turn on with the wiring in that place? If yes, then it could be Red or Blue are your C wire.

Assigning you know the G or green is actually your fan wire you can test the other wires for R. The fan should only turn on when you touch G to R. G to C should produce no fan sound (but the same thing would happens with G to W, or if either wire was shorted or disconnected elsewhere).

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Yes, the blue wire is "C" wire.

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