Purchased new 1994, no previous issues or service/repairs. Freezer temp/control dial historically set at "4", with setting adjusted to "7" (coldest) last year to maintain freezer temp. Presently, doesn't matter whether set at "7" or "1", changing the dial setting does not affect freezer temp.

Symptoms: Freezer no longer maintains temp of 0-5, condenser fan runs continuously except when defrost cycle initiated. Compressor warm/hot to touch but able to maintain hand on compressor without getting burned.

Recorded temps for last week: refrigerator temp 36- 40, freezer temp 10-16, occasionally 4-8 if freezer not opened, temp rises to 20-30 post defrost cycle.

Steps taken to date: coils cleaned/vacuumed from front access kit plate and back panel (removed); freezer door gasket inspected- appears competent, no visible tears, maintains seal; no air blockages in freezer or refrigerator apparent; no frost build up in freezer; defrost cycle duration is approximately 30 minutes, able to manually advance defrost timer to begin/end defrost cycle;
Purchased Defrost timer R0131577/AP4246797 from APP but have not installed as original timer appears to be functioning.
Purchased defrost thermostat PN10442411/AP4002416 from APP and installed. No affect on freezer temp. No frost noted on evaporator coils upon removal of freezer back panel when defrost thermostat installed.
Purchased Cold control C8946703 from APP but on back order. Removed existing cold control from freezer and tested while cold with multimeter for continuity. With cold control dial in "Off" position Ohm reading of 'infinity"/open, with cold control dial reset to highest/coldest setting "7", Ohm reading of "0"/closed; CC dial reset to "4" Ohm reading of "0"/closed; CC dial reset to "1" Ohm reading of "0"/closed;

Are the continuity test results consistent/expected with a functioning cold control?... or do the results indicate malfunction? If continuity results are as expected, can the cold control still be malfunctioning and causing the subject issue (e.g. condenser fan continuously run/freezer temp)? Are the continuity test results representative since tested the cold control when 'cold' versus room temperature?

If cold control not causing subject symptoms, then other suggested tests to reduce number of possible components?
Gladly answer questions. Thank you for your help, assistance and guidance.

Responses, guidance, your time and assistance appreciated. Thank you, denman.

Compressor runs simultaneously with condenser fan and evaporator fan.

Image if wiring diagram taken from back panel of unit is attached for reference.

Removed back panel in freezer (prior to initiation of defrost cycle; Refrig temp 36, freezer temp 8-10) and inspected evaporator coils.

Frost only visible on a small section beginning at the defrost thermostat location (encased in frost) and extending only a foot linearly along the coil. Attached images of same for your reference and review.

I reviewed your link (refrig...old enough) and associated images. Looks familiar.

Therefore, sealed system problem, and thus cold control part on back order not needed???

Based on your experience, leak, compressor failing, both or other?

Look forward to your help. Thank you!!

Post defrost cycle, Refrig/freezer evap fan/condenser fan/compressor operated for 8 hrs, refrig temp 36, freezer 12-14.

Per suggested procedure, removed rear panel in freezer to view evaporator coils, and obtained the following images 3180-1 and 3181-1 (attached for your review). Frost extended from defrost thermostat horizontially along the first coil but no further...pattern similar to previous post images.

Unplugged electric cord. Manually melted frost with blow dryer. Re-attached back panel. Plugged electric cord back in. Compressor, condenser fan and evap fan all operating. Let unit run for 1 hr 15 mins. Removed rear panel in freezer and obtained the attached image 3182-1. Frost pattern after the 1+ hr run time is similar to the pre-manual melt frost pattern.

Frost pattern evidence of sealed system problem? Or other?

Thank you, denman, in advance for your review and reply.

Reluctantly acknowledged.
Has been a solid, no problem unit for 20 years.
Thank you. Really do appreciate your help. Many blessings.