Here are your parts
Replacement parts for Frigidaire FRS26LF8CS2 Frigidaire/refrigerator | AppliancePartsPros.com

Here is the tech sheet
http://manuals.frigidaire.com/p...f/Anderson/240389616.pdf

And the operators manual
http://manuals.frigidaire.com/p...Anderson/240389311en.pdf

[COLOR="DarkRed"]do not know where the heater or the timer switch is located.[/COLOR]
The defrost heater is Item 14 in Section 9.
The unit uses a defrost board Item 23 in Section 2.
Also the defrost thermostat is Item 21 in Section 9.

[COLOR="DarkRed"]freezer is icing up and the blower motor for the evap core is not running.[/COLOR]
The most likely cause is the defrost board as it controls both defrost and the evaporator fan.

I would try to force a defrost cycle just to see if it will heat up.
If it does then I would replace the board.
If it does not heat up it does not eliminate the board as the problem and you will have to check the heater and the defrost thermostat. If both check out OK then I would replace the board.
Would not be a bad idea to check for 120 volts across the fan just in case it is toast and no fan and no defrost is just a coincidence.