I cannot find any info on the given model number.
Are you sure it is WV0 and not VW0?

The following is for a VW0 unit.

Here are the parts.
Parts for Whirlpool WED5300VW0 Dryer - AppliancePartsPros.com

See the attachment for the wiring diagram.

Is the air flow path in the unit including the blower wheel clean?
Make double sure that the vent system is clean and not kinked etc.
When you cleaned the vent system did you check that the louvers on the outside vent opened OK?

You have to check the heater with a meter.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 10 to 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case.
This can cause it to run on high.

The only thermostat that regulates the temperature if there is not a problem else where in the unit is the operating thermostat.
The others are safey devices and only have an effect it there is an over temperature problem.