[COLOR="DarkRed"]Could this simply be because of the defrost timer adjustment? I will get to it and tweak it a little just in case.[/COLOR]
There is no adjustment on a defrost timer. The defrost time and interval time are not adjustable.
When you turn the cam all you are doing is turning the cam inside the timer that the contacts ride on so am forcing the unit either into or out of a defrost cycle.

Here are your parts.
I could not find a KES2 so they are for a KES but should be close.
Replacement parts for MAYTAG MBL2556KES REF - BOTTOM MOUNTS | AppliancePartsPros.com

See the attachment note that it is for a KES5. but with luck the diagnostics will work.

First remove the evaporator cover in the freezer so you can see the coils.
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 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 control board needs replacing, re: it is not starting defrost cycles.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 15 in Section 5) 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 31 in Section 5) (clipped onto the evaporator coils) 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 board is toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.