[COLOR="Blue"]Can I set the timer so that the defrost heater will come on without having to wait?[/COLOR]
Yes just rotate the cam with a screw driver.
There is usually a hole in the unit cover to do this.
Note, that it only turns in one direction.
When the fans and compressor go off you are in a defrost cycle and the heater should heat up.
Be careful that you do not burn your fingers.
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What does 10hr/35min defrost timer mean? Does it mean the defrost heater will come on for 35min for every 10hrs the compressor operates?[/COLOR]
Yes it can.
On some units it is wired directly across power in so then you get a 35 minute defrost cycle every 10 hours.

[COLOR="Blue"]After I rotate the cam to test the heater, how much do I need to turn (180 degrees?) to move it back to the original setting?[/COLOR]
Just till the fans and compressor come back on, around 20 degrees.

The heater will only come on if the thermostat is functioning (closed - when cold), correct?
Yes, the thermostat must be frozen.

[COLOR="Blue"]What is the best way to ensure that the thermostat is frozen so that I can test the heater?[/COLOR]
You could just place the metal face of it on an ice cube, often you will hear it click closed.
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However, the resistence is only 22 ohms. Does that sound right to you?[/COLOR]
Yes the heater looks OK

Glad to hear you got it fixed.

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.