Ideally the thermostat should be mounted to a rafter along the wiring path and away from the draft of the fan.
Install attic fan thermostat switch.
Run a 12 3 w ground from switch box to fan thermostat box.
Leave enough cable at each end to work with.
Run nm cable from the attic fan thermostat to the attic light.
Mount the thermostat in the attic.
Staple the cable within 8 inches of both the attic light box and the thermostat box.
Use the hammer and staples to secure the cable to the joists at 12 inch intervals.
Screw this box to the plywood so it s in the direct path of the airflow step 11.
Step 1 secure the switch.
Start by screwing the thermostat switch to the plywood frame that houses the fan.
Place it so it s facing in the direction of the air that s being drawn out of the attic by the fan.