Wondering if there was a way to troubleshoot fan relay and blower motor thermal protect to tell if either of these were thr cause of my problem. Thanks

fan relay

If it is a stand alone relay then you can apply 24 volts to the proper terminals and see if the contacts close to activate the blower circuit.

If the relay is on a circuit board then you will be replacing the board.

motor thermal protect

In almost all residential cases the blower motor thermal protection system is built into the motor winding circuit. While you could not test this item without tearing the motor apart you can use a Amprobe to check the running amps of the motor and if lower than the motors rating and it goes off on the thermal protector in the motor then the thermal overload circuit is defective, the capacitor is bad or the voltage is improper. The motor will have to be replaced or you might find a rebuilder to repair it.

NOTE: While the above holds true for residential HVAC motor work commercial/industrial plays by a different game in many cases. Motor starters used by larger equipment will usually have heaters installed in them. When to much current is drawn the heaters will activate and drop the starter switch out of the circuit there by protecting the motor. This is just one example of many different ways protection can be done.

Class is over for today.