Open the Frigidaire and empty the dishwasher of all dishes and utensils.
Turn off the circuit breaker that controls power to the dishwasher.
Remove the screws in the kick plate at the bottom front on the left and right edges. Pull down on the plate and tilt it forward from the bottom to take it off the appliance.
Turn on the flashlight and direct the beam into the underside of the appliance. Locate the two terminals on the right side near the front where the internal heating element connects to the two wires underneath.
Follow the wires away from the heating element terminals to the thermostat, which is mounted on a flat metal plate with a second pair of wires.
Pull off the second pair of wires from the thermostat -- each slides off a metal contact. Remember where each wire attaches to the thermostat so you can reconnect them later.
Slide off the two wires on the other end of the thermostat. Leave the opposite ends of these wires connected to the heating element.
Hold one thermostat wire against the corresponding wire attached to the heating element. Wrap the blades on the two wires loosely with a 2-inch length of electrical tape. Eventually the wires must be separated, so do not wrap them too tightly. Repeat this step by wrapping together the remaining thermostat and heating element wires.
Close the Frigidaire door and switch on the circuit breaker.
Start the dishwasher on any cycle and run for five minutes.
Open the dishwasher door. If the water inside at the bottom is hot, continue testing the bypass.
Close the dishwasher door and set the appliance to the heated drying cycle. Run the dishwasher for five minutes and open the door.
Slide out the bottom dish rack and hold your hand above the heating element, making sure not to touch it. If you feel warmth from the element, the thermostat is defective and must be replaced.
Shut off the circuit breaker.
Remove the electrician's tape from the two pairs of wires. Do not turn on the circuit breaker until the thermostat is replaced and all wires are reattached.