I cannot find any info on your given model number but it sounds like you have a wiring diagram.
With luck your unit will be close to the following wiring diagram which is for a newer GE.
Can someone tell me where this switch is located and what the part is actually called?
It is called a centrifugal switch.
It is part of the motor. There are 2 of them and they are activated when the motor gets close to operating speed.
They are M1/M2 and M5/M6 on the diagram.
M5/M6 removes the start winding from the circuit and also provides a parallel circuit path for the start switch so that you can let go of it and the unit will continue to run.
M1/M2 switches in the heating element so that it does not come on until there is air flow.
As you can see you will see 120 (L1 voltage) at the heating coil as long as the timer is on a heat cycle.
Have you checked for 240 volts between L1 and L2?
This is the voltage required for the heating element.
Try flipping the breaker off/on slowly a couple times.
Sometimes you can loose half the line without actually tripping the breaker.
If this does nothing, check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
Check the power at the terminal strip.
Be careful as 240 volts is lethal !!!
Would this be the switch interlock?...
I do not think so. They may be talking about the door switch.