Here are your parts includes a wiring diagram
Replacement parts for MAYTAG MTB2456DEW REF - TOP MOUNT | AppliancePartsPros.com[COLOR="DarkRed"]seemed as though it was not defrosting. the freezer
temp was 25 and the frig temp was 55. i removed the freezer back
panel [/COLOR]
You did not say but if the evaporator coils were not heavily frosted/iced over then you do not have a defrost problem.
[COLOR="DarkRed"]and took a ohm reading on the heater. it read 30 ohms.
in your wiring diagram it says it should read 240k ohms. i by passed
the defrost thermostat and intiated a defrost cycle and the heater
got hot.[/COLOR]
No the 240K ohms is for the defrost thermostat when it is open.
The 30 ohms for the heater is OK.
[COLOR="DarkRed"]
how do you test the defrost thermostat, with freeze spray?
the timer is and heater both seem to be working.[/COLOR]
The defrost thermostat is in series with the heater and since the heater came on I would say the defrost thermostat is OK.
Forcing a defrost cycle only checks the contacts in the timer and not the motor/gearing.
Odds are that the timer is sticking somewhere during the cycle.
I would replace the defrost timer.