Need help troubleshooting Samsung RS2555SL

[boblane]

Hi, I'm hoping to find some updated help on a similar problem that I am having with my Samsung fridge that i have seen discussed here.
My Symptoms: The fridge stops cooling. Upon removal of the fridge section, the Evaportor coils are frozen with ice. The vent to the fan is iced up as well. I manually defrost everything, and the fridge cools properly for about 2 days. Then the cycle repeats.

The fan works, I have taken it apart and verified the fan spins with the door thingy pushed shut.

I have replaced the defrost sensor once, with no change. One mystery for me here, if I measure the resistance of the old defrost sensor, with a multi-meter across the two connectors, it shows open. Am I measuring this properly? I didn't measure the new one before installing it, but it too measures open now that I have measured it.

Based on the timing that it takes for it to ice back up, I am assuming that the defrost heater is never coming on. I'm hoping the defrost heater isn't toast, but could use some tips on determining for certain whether or not another component is at fault.

Thanks, Bob

[spimps]

Samsung have modified the fan cowling and also a metal clip comes with the new fan assembly which clips onto the defrost heater and when the fan housing is fitted it makes contact with the metal plate ensuring decent heat transfer to clear the fan vent of ice.
Should have a reading of 265ohms on the defrost element,there is also a heater embedded in the drain tray underneath the evaporator.
Frost sensor should have a reading of 5kh at 25c, ambient temperature.

[boblane]

Ok, knucklehead move, I measured the defrost sensor with the meter's setting too low. It actually measures about 6.5k ohms at room temperature, so the original sensor seems to not be the problem.

I have read about the modified panel with the metal plate. While that would probably be helpful, I don't think it is the main problem I have in that the fan works fine until so much ice creeps up from the evap coils.

My next step, again hoping the defrost heater isn't shot, is to replace the thermo fuse.

Last bit, when the unit is plugged in, it displays the number 3, which if I read the manual correctly, is pointing at the r. defrost sensor.
Any thoughts or opinions? What should I be measuring to check if the heater is functional?