Whirlpool top freezer with all electronic controls and thermistor in refrig for refrig temp and a thermistor in the freezer in place of the defrost bi-metal.
This is the first of these newer style all electronic controls that I've worked on so had no idea of how to put into defrost to try and test the defrost system. Looked for the tech sheet in the control box area and under front behind kickplate and couldn't find it so went about defrosting and trying to figure out the problem.
After defrosting, I find no defrost bi-metal but instead a thermistor which read 970 ohms the first time I checked it just after I had removed all the ice from around it and it basically fell off the suction line. I reattached it to the suction line, (it was really loose), and took another reading and the resistance was going up - read around 1700 ohms. After I took it out again and squeezed the mounting clip tighter so that it would hold onto the suction line better, it was reading around 2600 ohms which is where it seemed to hold at, (this is all while warm - forgot to check the thermistor again after defrosting and starting it back up).
I have no idea what the specs on the freezer defrost thermistor should be.
When I finally found the tech sheet, (they are hiding them in the compressor compartment clipped to the back rail behind compressor cover), and found how to put into diagnostic mode all outputs worked except of course defrost - don't know if the diagnostic mode defrost check requires the thermistor to be cold or not, (heater didn't come on/ zero amps during defrost test/ heater ohms out OK at 36.5 ohms).
The tech sheet says that if there are failure codes to be displayed they will show by blinking the LED1-4 lights after step 7. If multiple failures are detected the major fail is shown. It doesn't show any error code were all four LED's would be flashing at the same time, which is what I get.
Hopefully someone can get me a service manual for these, (I requested one in the manual request section), or at least the specs on the thermistors.
Some input from others that have worked on this newer style unit would also be greatly appreciated.
Attached is this tech sheet: W10414768, (page 2 only, page 1 is over 200kb and page 3 is just the wiring diagram)
Edited by Budget Appliance Repair, 21 December 2012 - 07:44 AM.