Low heat only works

I can only get my dryer to turn on in the low heat mode. Any high heat mode and anything else will not work/run. I have checked continuity through all of the fuses and ohmed out the resistors and everything seems to check fine. I am by no means an electrician so I may be missing something. Anyone have any ideas?

Here are your parts
Replacement parts for WHIRLPOOL LER4634EQ0 | AppliancePartsPros.com

Here is the wiring diagram
http://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%203401728.pdf

As you can see from the wiring diagram the only heating device that can effect the motor is the thermal fuse and once blows it stays blown.

Since the unit runs in low heat we know the door switch, push to start switch, motor and thermal fuse are all OK. All that is left is the BU/BK timer contacts.

To check this
You could unplug the unit
Set it where it runs and check these contacts for continuity.
Should be 0 ohms
Then put it to a cycle that does not run and odds are the contacts are infinite ohms..