My aqua glass whirlpool tub's motor will just start by itself sometimes in the middle of the night.

http://www.aquaglass.com/product-assets/installation-manuals/07397%20All%20Whirlpools.pdf

no power
motor seized up
thermal overload button needs pressing in

it is a air switch, it has a tube running from the button to a box mounted on the pump motor,it could the hose has came off

First of all, what you have is a WOW pump that has an E-switch for a control.
There is a knob on the top lip of your tub that you turn a 1/4 turn to turn this pump on/off.
There is a small circuit board inside the box on top of the motor. This is likely the source of your problem.
Here is your biggest problem. That little circuit board is not made anymore. We have the e-switch but you will be better off changing out the pump (which you have to do anyway) with a new WOW pump with an air switch and change the switch on the top lip of the tub to an air button which will turn the pump on/off.

Rod
US Parts Center

Air Switch Repair
It sounds like you have a bad air switch located in your motor.
The air switch is what the air hose connects to on the back of the motor or on the box on top of the motor. The other end of the air hose is connected to the air button on the lip of the tub.
This is a latching air switch and when you push the air button it latches to send power to the motor. When the air button is pushed again it opens the latch in the air switch and stops power going to the motor shutting it off.
888-521-6183
US Parts Center

Check the circuit breaker and make sure you have power to the pump.
If you have power to the pump and it is not operational when the tub is full of water and you are in it then I would say you have a serious problem.
Most all of the older control that Aquaglass has used in the past have been discontinued.
You may want to visit this link and identify your control before you begin t trouble shoot your system.

Rod
US Parts Center
888-521-6183

We have all the old Aquaglass switches or the replacement for the ones that are not made anymore. Aquaglass Parts
Contact us at: [email protected] or Toll Free 888-521-6183

Rod
US Parts Center

Your motor is shot. you need a new pump. If it comes on and you can hear a hum then it is bad. If you can get us a model number of the pump we can recommend a replacement model for you.

US Parts Center

will have to remove access panel or make one the motor /pump assembly is mounted to the tub test for power to the switch and pump the numbers u are looking for are their by pump

To my knowledge there are no closure caps for your tub; you can however purchase new jets with new seals if the tub is leaking through the jets.