I cannot find any info on this unit so the below is just general.

Here are a couple good sites with basic test etc. info
http://www.applianceaid.com/frig.html
Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com

First you have to find out if the compressor is running.
You should be able to hear it and feel it vibrating.
If yes
Then check to see if the fan in the freezer is running. It is required to push the cold air down into the fresh food section.
NOTE: if neither the compressor or the evaporator fan is running you may be stuck in a defrost cycle.
If OK
Remove the evaporator cover from inside the freezer so you can see the coils.
If they are heavily frosted/iced over you have a defrost problem.
Check to see what type of defrost timer you have re: an electric timer or an electronic adaptive defrost board.
Often the timer is in the console at the top of the fresh food section.
There may be a hole in the cover so you can force a defrost if it is an electric timer.
Sometimes they put an electric timer at the bottom behind the kick plate.
See at the bottom of this post on how to trou8bleshoot a defrost problem.

If there is just frost on one area of the evaporator coils you probably are low on freon and have a leak in your sealed system.

Defrost Troubleshooting
First remove the evaporator cover in the freezer so you can see the coils.
Not do not let them de-ice.
If they are heavily iced/frosted over you have a defrost problem.

If yes.
Manually force a defrost cycle by turning the defrost timer cam (Item in Section ) till the fans and compressor turn off.
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the timer needs replacing, re: it is probably stalling during it's rotation so is never getting into a defrost cycle.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item in Section ) from the wiring and measure it for continuity, usually around 20 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat (Item in Section ) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.

If both the above are OK then odds are the defrost timer contacts are toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.

There is a good STICKY at the start of this forum about it's use.