Spa type: 1986 Hot Springs Classic model E

Question: tub includes three mercury-filled, copper sensors (thermistors?) with capillary tubes which lead to the two GFCI switches and one leading to the thermostat. The two from the GFCI switches are high limit sensors etc. What I would like to ascertain is the correct position of the sensors. That is, I’m fairly sure one goes in the middle of the heater and one goes in the middle of the circulation pump but I’m not clear on where the thermostat sensor goes.
Does anyone know? Thanks.

I can't recall exactly what the motor compartment looks like in an '86 classic, but I believe the thermostat capillary bulb may slide into a dry well in the base of the compartment. Do you see any openings about 3/4" in diameter? Most slide in there and then you seal the opening with some foam or plumber's putty.

I don't know of any probes that go into the circulaion pump.

Can you take a pic of the compartment?

There's a 2" pipe on the left inside the equpiment door. The end is fitted with a cap that serves as a drywell. It was originally wrapped in a brown foam insulation. The heater high limit bulb goes into the heater. The tub high limit and the thermistat go onto the pvc drywell. Happy Thanksgiving.