Model #MSB2154GRW water leaking from out of the front of the unit apparently when defrost cycle runs. Suspect blocked or defective evaporator unit. How do I access this to examine the problem?

This is caused by a blocked defrost drain. The defrost cycle is normally overnight and the condensate that is defrosted from the evaporator fins is supposed to drain into a pan near the compressor where it evaporates. Look on the external and internal rear of the unit for a pipe and a u-bend.

Check the drip tray in the freezer section where defrost water drips from the defrost heater melting frost during the defrost cycle. If ice blocks the drain hole in the tray inside the freezer(usually behind the evaporator cover) the defrost water will travel into the bottom of the freezer & onto your floor. Some models also have a second evaporator in the fresh food section. A blocked drain or clogged defrost drain tube can cause the problem.

Is the water leaking from the door, onto the floor in front. If so, probably a blocked drain outlet or pipe. At the bottom rear of the unit, mine had a drain pipe blocked with a plug of mould (5/6 years old machine), apparently quite common. I detached the pipe and cleaned it out and replaced it.
From inside the freezer, I removed the lower back panel and thawed the ice build up on the drainage tray below the defrost heating element, leading to the pipe outside. The puddles of water that was appearing every defrost cycle have now stopped - permanently I hope. Hope this helps you

Hi and welcome to FixYa, I am Kelly

First off make sure the water in door still works. If it does not work suspect the door / light switch.
Next make sure the freezer temp is below 16 Deg F. The ice maker has a thermostat that starts the ice harvest / fill cycle and if the freezer is warming up because of automatic defrosting problems (Ice build up on the evaporator coils) the ice maker will never cycle. If you note an ice build up in the back of the freezer compartment or poor air flow from the evaporator fan you have an automatic defrosting problem. If the fan is not running at full speed the bearings or windings on the evaporator fan are failing and there is not enough air flow to get the freezer to @ or Below 16 F.

Check to make sure the evaporator fan in the freezer and the condenser fan in the rear bottom of the unit are running un-obstructed. (clean as necessary.... but if the front of the cabinet is hot to the touch then the condenser coils my be clogged with lint or... the condenser fan is not running full speed.

The ice maker may be cycling but it may not be filling with water. If it is cycling but your not getting any water.... at all the prime suspect is the solenoid on the inlet water valve. The water valve is not repairable.

Make sure that the rubber fill tube on the back of ice maker is not blocked with ice... squeeze the end of the tube. If it is frozen with ice... the inlet water valve is bypassing water off cycle and causing the tube to freeze up. The only remedy for this is to replace the inlet water valve.

Thanks for choosing FixYa,
Kelly

There is a leak or damage of the pipe leading from the evaporator downwards.The defrosted water is leaking out of the tubing to the bottom,replace this tubing or check the leak on the collecting tray under the evaporator.

Is it leaking out of the evaporator(inside unit) or condenser?

If it is leaking from the outside unit on defrost then it is normal, if it is leaking from the inside unit then you have a blocked condensate drain tube!

These units defrost from time to time and is normal, it is actually melting the ice that can form on the condenser when it is cold enough outside, it has to initiate a defrost cycle so that air can flow through the condenser again after the cycle is complete.

Then it will return to normal heat pump mode, this is assuming that you have a heat pump.

If the water is actually coming from under the ice maker, I can't help you.
However, I just discovered water leaking from around the top of the lid on mine. I took the lid off [by first removing both side panels and then the screws for the top] and discovered that there is a metal plate under the water spout that causes water to splash up around the lid. In mine, this led to water running out aall the way around the lid, down the sides, and all over the counter. You can't remove the spout without messing up the water level sensor, but I bent the plate a bit flatter and no longer have splashing water everywhere.

There is a small fan that draws air across the condenser coils and evaporates water that accumulates from the self-defrost cycle.

Be sure the condenser coils (on the bottom of the refrigerator) are clean and that the small fan is working. The water is most likely from the self-defrost cycle that is not evaporating properly.

I have a strong suspicion that the fan is defective. Remove the back of the unit and see if it is running. And I can't overstate the importance of cleaning the coils. Dirty coils are the #1 cause of refrigerator inefficiency something as simple as cleaning them can make a world of difference in the efficiency of the unit.

if the freezer is getting cold the problem is due to the cold air from the freezer not getting into the refrigerator. There are several things that can cause this problem. The coils in the freezer icing up and not defrosting properly is one of the things that can cause the refrigerator not to get cold enough. Another problem is the fan that blows the cold air from the freezer compartment into the refrigerator, not working. When the compressor is running open the refrigerator's door and push the switch that makes the light go out. You should hear the fan blowing the cold air from the freezer into the refrigerator, when this switch is pushed in. If the fan is working then you will need to find what is blocking the air flow. Iced up coils are a common problem. The icing problem can be due to a defective defrost timer or something defective in the defrost circuit. Click here for more information. Check for these problems and let me know what you have found.
REFRIGERATOR TROUBLESHOOTING
#1 Refrigerator side getting warm Freezer still cold
Evaporator fan motor not running.
Defective defrost timer. See Defrost Diagnosis Procedure
Defrost heater defective. See Defrost Diagnosis Procedure
Defrost thermostat defective. See Defrost Diagnosis Procedure
Airflow blocked from freezer compartment.
Freezer control turned to "coldest" setting blocking air flow to refrigerator side. On most refrigerator/freezers, the freezer control closes a baffle when turned to coldest setting, and this blocks off the air flow to the fresh food compartment.
Fan blade broken.
Defective door switch on older models.
Light staying on with door closed.
2 Refrigerator & freezer compartments both are getting warm
Make sure refrigerator is plugged in and has power.
Condenser fan motor on bottom under refrigerator not running.
Condenser coil clogged.
Defective defrost timer. See Defrost Diagnosis Procedure
Defective defrost heater. See Defrost Diagnosis Procedure
Defective defrost thermostat. See Defrost Diagnosis Procedure
Evaporator fan motor not running.
Cold control defective.
Compressor overload defective.
Compressor relay defective.
Light staying on with door closed.
Compressor defective.
Low on refrigerant. #3 Freezer compartment getting hot.
Defrost timer stuck in defrost cycle.(replace)
Defrost thermostat stuck.(replace)
Ice maker stuck in harvest cycle
Light staying on with door closed. 4 Ice maker not making ice
Defective inlet water valve.
Freezer temperature not cold enough. (see problem # 2 & 3 above)
Defective thermostat in ice maker.
Defective drive motor.
Water inlet tube clogged with ice.
Defective module in newer style icemaker. 5 Refrigerator sweating around door edges
Door gaskets leaking air.
Defective case heaters.
Energy saver switch not set to reduce exterior moisture
also if require more help click the link http://www.applianceaid.com/refrigerator.html please do rate the solution .thanks in advance.thank you for using fixya.

sounds like your defrost drain is stopped up its under the evaporator clear it and you should be ok