1 
1 Evaporator Fan not Working. Have power at plug.
KitchenAid KSCS25FVMS01. 11 Years old - manufactured Sep 2008.
Compressor is working, freezer coils getting cold.
Bottom of freezer is cold, crisper drawer in fridge cold, but the rest of the refrigerator is warm. Ice maker and water dispenser work when evaporator fan motor runs, but don’t work without evaporator fan motor.
No air circulation, fan does not start even though there is 12VDC across red and white wires to evaporator fan..
Here is what I tried already:
1) cleaned compressor coils under refrigerator. They weren’t very dirty, but thought this was the easiest place to start.
2) replaced fan motor with identical replacement. Panasonic UDQT22WP1, 12V DC, 3.0 Watt, Model 2259385. Refrigerator worked for 5 weeks, then stopped again same problem. Confirmed 12V DC at plug. Removed fan and applied 12V DC using alarm battery across red/white terminals. Neither old fan, nor brand new fan motor started.
2) replaced bi-metal thermostat because the old one was pitted. Ice caked up on freezer coils. Did not appear that defroster was working. Old thermostat did not have continuity. Tested the new thermostat - continuity when frozen, no continuity when warm. Installed and freezer coils are cold, but not frozen solid as before.
3) replaced control board assembly. No change in performance. Lights in fridge and freezer go on/off when doors open/close. temperature controls appear to work and respond to +/- arrows. Power off turns off, on turns on.
4) bought a 3rd fan motor from different supplier. Still have 12V at plug, but fan motor does not start either on the bench or in the freezer.
5) Unplugged refrigerator overnight to completely defrost and discharge any static electricity. Restarted, no change.
3 different fan motors, none start. 2 different control boards, no change in performance.
What am I missing?
Hi,
Just curious. Just trying to eliminate possibilities
Did you measure the resistance of the fan motor across the red/white wires?
According to the specs for the fan it should read approx. 48 Ohms (12 V @ 3W).
Also with the 3rd fan did you try it on the bench before you installed it or after?
Did you measure the voltage with the fan connected to the supply from the control board?
Did you test for continuity of the blue and yellow wires back to the control board from the fan connector? I assume that one might be a speed sensor connection or possibly both wires to the one sensor.
Usually 4 wire fans, in PCs anyway, besides batt and earth wires, the other two connect to a thermistor for temp sensing and a hall effect sensor for rpm (usually connected through to the earth lead in the fan) but can't see why a temp sensor would be necessary on a evap fan when there are other sensors in the freezer for this. If there is no sensor lead working the fan isn't started Just a thought.
由 jayeff 完成的
Thanks for the comment.
I tested voltage on the back of the plug to the motor, so no need to check continuity back to the board on the fridge side. I'm sure one of the other wires is a speed sensor, but don't know which one or the correct range. I'll trace the wires and check continuity tomorrow.
Fridge and freezer temps are reported on the display screen in the fridge, so I assumed the thermistors worked properly.
Resistance across red/white was weird. I didn't get a continuous resistance, just a temporary flash of 5-159 ohms, then to infinity. I tried turning the motor shaft by hand to see if resistance would fluctuate with winding position. No. It feels like a stepper motor because the motor turns notch to notch, not spinning continuously.
由 gint 完成的
Hi,
if you are right and it is some sort of stepper motor here's how to check the windings or if it is some sort of PWM motor control then a speed sensor would come into play.
No doubt since you have replaced the fan 3 times and also the control board it puts emphasis on making sure that the wires going from the fan connector back to the control board have continuity.
Double check the fridge side fan connector itself in case the connector pins (male/female?)have lost tension (or maybe a loosely crimped wire - gently tug the wires at the back of the connector and make sure that it stays in - don't pull too hard as you can pull them out accidentally if too forceful) and are not connecting through properly when the fan is plugged in
由 jayeff 完成的
I was going to trace wires this morning, and lo and behold the evaporator fan was working and the refrigerator came back to life. I'm guessing the fridge was stuck in a defrost cycle. These newer refrigerators don't have the old manual timer switches, but are timed by silicon on the control board. All the sensors have to be right, or like mine, the refrigerator is in limbo. I was going to go back and plug in the old fan motors, but think I'll just leave well enough alone instead.
由 gint 完成的