Dryer heats on one cycle only

Dryer heats on one cycle only

I have a Whirlpool LGR5636JQ0 gas dryer that has 4 drying cycles - Automatic (High Heat), Automatic (Low Heat), Air Fluff and Timed Drying with cool-down. The only cycle that produces heat is the Timed Drying. I've replaced the thermostat and fuse, and cleaned the internal air chute and the lint hose. Is this an issue with the temperature selector? Thanks in advance.

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