Freezer is at proper temperature.
If it is a defrost problem it usually shows up in the fresh food section first.

There is frost on everything and the unit keeps running.
I am assuming you mean the food in the freezer.
This could be caused by a leaking door seal.
Check that the seals are not catching or curling over on the hinge side of the doors. If it is a light coating of grease/vaseline often solves this.
Take a 2 inch piece of paper or a dollar bill and place it between the seal and the frame then pull it out you should feel some resistance. Work your way around the doors to find a seal leak. Also check the seals for rips etc.

Turned defrost knob until it clicked. Still kept running.
I could not find info on this unit so am assuming that the above refers to a mechanical defrost timer. If you rotated the cam a full 360 degrees and it did not go into a defrost cycle then you have a bad defrost timer.

No ice buildup.
Are you referring to the evaporator coils?

Coils are not dirty.
Which ones the condenser/compressor or the evaporator (freezer)?