Hi and welcome to
FixYa, I am Kelly.
There are 4 models of the
unit and the last digit indicates color that
being an B, S, Q or W. For reference purposes I will use the B model. Having said that... things that can cause your symptom are:
1. The control board Item 5 this link:
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5167295&diagram_id=28326675#d28326675
2. The defrost themostat that is the very last item on this page: (no item number listed)
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5167295&diagram_id=28326676#d28326676
3. The defrost heating element Item 15 above link.
4. The termistor Item 22 of this link:
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5167295&diagram_id=28326675#d28326675
5. The PTC relay / overload protector or the run capacitor items 10 and 11 this link:
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5167295&diagram_id=28326674#d28326674
6. The compressor Item 8 of the above link:
Those are all things that can cause your problem. It takes component testing and replacement to isolate which one of them is causing the problem.
For example... if the unit is in defrost the compressor does not run. If the defrost thermostat has failed it will never terminate the defrost cycle so the lights will be on but the compresser will never start. Also.. if the heater has failed... the Freezer will have to warm up to 60 deg F before the compressor will restart. If the compressor is trying to start about every 5 to 6 minutes the PTC / overload protector has failed. When this happens the PTC / Overload and the run capacitor are all replaced at the same time. (<- before changing these parts if the compressor is HOT unplug the unit for 20 minutes and wait for the comressor to cool down then try and restart it) A bad control board.... or an open /shorted compressor winding can cause a dead unit. There are other examples... but these are the most common.
Just a note about your unit if the fans are on and the compressor is NOT running you need to look at the compressor only as where the problem lies. (relay overload cap and or compressor / compressor wiring).
You can try doing a manual defrost by directing an external fan into the freezer compartment for 2 hours. (Makes a water mess) In your case your trying to get the defrost bi-metal thermostat to 60 Deg F so that the signal to start the compressor is present. (provided the defrost thermostat is good) Other than that the only option is to troubleshoot using this wiring diagram:
http://www.appliancepartspros.com/partsearch/frame_diagram.aspx?diagram_id=28326683&pkw_=basket&model_id=5167295&NewWindow=1
Thanks for choosing
FixYa,
Kelly