Heat Pumps and Electric Heating - outdoor fan stops

My Goodman mod. 13GSH does not seem to defrost properly, the fan shuts off but the line continues to be warm and no defrost. I know that the rev. valve works because the ac works and the defrost will work in man.mode is it the def. bd or the thermostat, i also know that it has a frost sensor as I can see it attached to the coil line with 2 red wires and going to the def. bd. please help.

Not that familiar with the goodman defrost controls can you explain how it functions and how you initiate the defrost control manually please. I see that Goodman recommends the following is OPERATION - DEFROST CONTROL
Timing
When operating, the power to the circuit board is controlled
by a temperature sensor which is clamped to a return bend
on the outdoor coil. Timing periods of 30, 60, or 90 minutes
may be selected by connecting the circuit board jumper wire
to 30, 60, 90 respectively. Accumulation of time for the timing
period selected starts when the sensor closes (approximately
28°F) and when the wall thermostat is calling for heat. At the
end of the timing period, a defrost cycle will be initiated,
provided the sensor remains closed. When the sensor opens
(approximately 65°F), the defrost cycle is terminated. If the
defrost cycle is not terminated due to the sensor temperature,
a 10 minute override interrupts the defrost period.
Field Testing / Trouble Shooting
A. Run unit in heat mode.
B. Check unit for proper charge. Note: Bands of frost indicate
low refrigerant charge
C. Shut off power to unit.
D. Disconnect outdoor fan by removing the purple lead from
"DF2" on defrost control.
E. Restart unit and allow frost to accumulate.
F. After a few minutes of operation, the defrost thermostat
should close. To verify this, check for 24 volts between
"DFT" and "C" on board. If the temperature at the
thermostat is less than 28°F and the thermostat is open,
replace the thermostat as it is defective.
G. When the defrost thermostat has closed, short the "test"
pins on the board until the reversing valve shifts,
indicating defrost. This could take up to 21 seconds
depending on what timing period the board is set on.
After defrost initiation, the short must instantly be removed
or the defrost period will only last 2.3 seconds.
H. After the defrost has terminated, check the defrost
thermostat for 24 volts between "DFT" and "C". The
reading should indicate 0 volts (open sensor).
I. Shut off power to unit.
J. Replace outdoor fan motor lead and turn on power.this what you are doing?

Thanks for the reply former mem. I have not done any of what has been mentioned. I will attempt sometime this week. I will keep posted here.

Be careful and follow all the directions carefully as you can easily BURN out your control board if you do this wrong. If you do not understand it you may want to phone a friend or use a lifeline or just post back for further direction.

I never touched a thing and now it seems to be defrosting, seems I had this prob. last winter also. I will keep an eye on it and post back any further developments

If the defrost sensor is easy to get to pop it off the line and sand the line clean plus the mating surface of the sensor and reinstall it might just have some corrosion underneath it