[COLOR="Blue"]Also, Continuity across the red and yellow terminal of the heat selector switch.[/COLOR]
This of course depends on your heat setting

[COLOR="Blue"]There is no continuity across the blue and white-red terminals.[/COLOR]
Sort of loosing me here as the Blue to White-Red is across the heating coil so if there is no continuity the coil is toast but you said it checked out OK.

[COLOR="Blue"]The wierd thing is that the white-red wire was showing 120 volts even when the dryer was not spinning.[/COLOR]
If I turned the timer knob to off, the voltage would go away.
Depends where the other meter lead is. If it is on Neutral of machine frame then you will see the L1 voltage. Circuit path is L1 , TM/A timer contacts , 377 K resistor , R timer connection , Red wire , heating element Red and White-Red wire.

Note that you will see the same voltage on both sides of a component when it is not passing current. Unless of coarse the component is open (infinite resistance).

[COLOR="Blue"]This was also intermitent as I was taking things on and off to test the most recent time the white-red wire would only show 120volts when the dryer was running and would go to zero when the door switch was open to stop the spinning.[/COLOR]
Cannot comment as I do not know where the other meter lead is.

[COLOR="Blue"]I will replace the heat selector switch today, but it seems there is probably some other problem.[/COLOR]
I think the heat selector should be:
No heat : L1 to C and 1 both open
Low heat : L1 to C and 1 both closed
High heat : L1 to C closed , L1 to 1 open

[COLOR="Blue"]Could be in the Motor Switch?[/COLOR]
Yes but lets back up.

Have you checked that you have 240 volts (L1 to L2)
Check it at the plug and the terminal strip in the unit.
[COLOR="Red"]Be careful 240 volts is lethal[/COLOR]
IF OK
Unplug the unit.
Attach/tape one of your meter leads to the L timer connection.
Set your meter to a low scale (200 ohms)
Set the timer to mid scale timed dry and the heat to high.
Then work your way back through the circuit.
You should see 0 ohms all the way back to the RED (thermostat) side of the heating coil.
Then approximately 12 ohms at the RED and WHITE-RED side of the coil.

If you do then all that is left in the circuit is the centrifugal switch.

good luck, I hope the above makes sense.

[COLOR="Blue"]Thanks for your help.[/COLOR]
You are welcome.

And thanks for getting back to us. Now when others search for a similar problem they will see what actually worked instead of just suggestions about what could be the cause.