Samsung RT18M6215SG (Top Freezer) – Ice buildup in freezer Repair Guide

🔧 Ice Buildup in Freezer Repair Guide for Samsung RT18M6215SG (Top Freezer)

💡 Don’t panic! Replace defrost sensor/heater; check auto-defrost timer

📋 What You’ll Need

• Defrost sensor
• Defrost heater
• Defrost timer

🔧 Step-by-Step Repair Instructions

🔧 Step 1: Test Defrost Sensor Operation

1. Unplug the refrigerator from the wall outlet and wait 5 minutes for any residual electrical charge to dissipate.
2. Open the freezer door and remove all food items, shelves, and bins to get to the rear wall panel.
3. Find the 4 Phillips-head screws securing the white plastic evaporator cover panel on the rear wall of the freezer—2 at the top corners and 2 at the bottom corners.
4. Remove all 4 screws with a Phillips #2 screwdriver and keep them in a container.
5. Grip the evaporator cover panel on both sides and pull it straight forward, then lift it upward to unhook from the bottom clips. Set the panel aside.
6. Locate the defrost sensor—a small cylindrical component (about 1 inch long, ¼ inch in diameter) with 2 wires attached, clipped onto the evaporator coils on the left side, roughly 8 inches from the bottom.
7. Disconnect the 2-wire connector from the defrost sensor by pressing the plastic tab and pulling the connector straight back.
8. Set your multimeter to the ohms (Ω) setting on the 20K or 200K range.
9. Touch one multimeter probe to each terminal on the defrost sensor’s connector pins.
10. Read the resistance value—at room temperature (68-72°F), the sensor should show between 5,000 and 20,000 ohms. If it reads “OL” (open line) or “0” ohms, the sensor has failed.
11. For a secondary test, wrap the sensor in a bag with ice cubes for 3 minutes, then retest—the resistance should increase to 40,000-60,000 ohms at 32°F.
12. If readings fall outside these ranges in either test, the defrost sensor needs replacing (Samsung part number DA32-00006W).

🛠️ Step 2: Check Defrost Heater Continuity

1. Locate the defrost heater inside the freezer compartment, mounted beneath the evaporator coils at the back wall, running horizontally across the bottom of the coil assembly about 2 inches above the drain pan.
2. Identify the two wire connectors attached to the defrost heater terminals—one on each end of the glass tube heater element, typically covered with white or clear plastic connector housings.
3. Grip the wire connector on the left side of the heater and pull straight away from the terminal to disconnect it.
4. Repeat for the right side wire connector, pulling straight out until it releases from the terminal.
5. Set your multimeter to the ohms (Ω) setting at the lowest range, typically 200 ohms or the continuity setting if available.
6. Touch one multimeter probe to the left metal terminal of the defrost heater where the wire was connected.
7. Touch the other multimeter probe to the right metal terminal of the defrost heater.
8. Read the multimeter display—a functional defrost heater will show between 25 and 50 ohms of resistance (Samsung part DA47-00244B typically reads 33-37 ohms at room temperature).
9. If the multimeter displays “OL” (overload), “1”, or an infinity symbol, the heater element has failed and needs replacing.
10. If the reading is within the 25-50 ohm range, the defrost heater is working correctly. Reconnect both wire connectors by pushing them firmly onto each terminal until they seat completely against the plastic heater housing.
11. If a replacement is needed, remove the single metal mounting clip securing the center of the heater tube by squeezing the clip ends together with needle-nose pliers and sliding it off the mounting bracket.
12. Take note of the heater position and routing before removal for accurate reinstallation of the new part.

⚙️ Step 3: Verify Auto-Defrost Timer

1. Locate the defrost timer in the fresh food compartment (refrigerator section), mounted on the right side wall near the top, approximately 2 inches down from the ceiling and 1 inch from the back wall.
2. Remove the white plastic cover plate by pulling the bottom edge forward and lifting up to release the two top clips.
3. Identify the defrost timer—it’s a white rectangular component measuring around 2.5 inches x 2 inches with a 4-pin connector and a manual advance dial on the front face.
4. Set your multimeter to the continuity setting (ohms symbol with sound waves).
5. Unplug the 4-pin connector from the timer by pressing the release tab on top and pulling straight out—you’ll see white, yellow, orange, and brown wires.
6. Insert one multimeter probe into the terminal slot for the brown wire (compressor contact, pin 1) and the other probe into the white wire slot (common, pin 2).
7. Rotate the manual advance dial clockwise slowly—you should hear a click approximately every quarter turn, and the multimeter should show continuity (beep) in certain positions and no continuity in others.
8. Test between brown wire terminal (pin 1) and orange wire terminal (pin 3—heater contact)—rotate the dial and verify the opposite pattern from step 6, where one circuit opens as the other closes.
9. If both tests show proper switching action (continuity alternates between circuits), the timer functions correctly—reconnect the 4-pin connector until it clicks into place.
10. If either test fails (no continuity changes or no clicking sound), replace the timer with Samsung part number DA47-00244C.
11. Reinstall the white cover plate by inserting the top clips first, then pressing the bottom edge until both lower clips snap into position.

🔩 Step 4: Replace Faulty Defrost Components

1. Locate the defrost heater, a glass tube approximately 18 inches long mounted horizontally beneath the evaporator coils in the freezer compartment.
2. Remove the 2 metal clips securing each end of the heater by squeezing them with needle-nose pliers and sliding them off the rubber grommets.
3. Disconnect the white wire connector on the left side and the white wire connector on the right side by pulling straight away from the heater terminals—no twisting required.
4. Slide the old heater out of the rubber grommets on both ends.
5. Insert the new defrost heater (part number DA47-00244B) into the rubber grommets, pushing until 1 inch of the heater extends past each grommet.
6. Reconnect the white wire connectors to each terminal until they snap into place with an audible click.
7. Replace the 2 metal clips by sliding them over the rubber grommets to secure the heater.
8. Locate the defrost thermostat attached to the evaporator coil tubing on the upper left side, approximately 4 inches from the top.
9. Use a Phillips-head screwdriver #2 to remove the single mounting screw securing the metal bracket.
10. Disconnect the blue wire connector by pulling the female spade terminal straight off—you’ll see one wire coming from the main harness.
11. Remove the thermostat from its metal clip by sliding it upward.
12. Insert the new defrost thermostat (part number DA47-00095G, rated at 41°F close temperature) into the metal bracket, sliding downward until it seats against the coil tube.
13. Reconnect the blue wire connector by pushing the spade terminal onto the thermostat tab until it seats completely—test by gently tugging; it should not pull off.
14. Reinstall the mounting screw, tightening until the bracket is snug against the coil—approximately 3-4 inch-pounds of torque.

📋 Step 5: Manually Defrost Freezer

1. Unplug the refrigerator from the wall outlet to cut all power to the unit.
2. Open the freezer door and remove all food items, placing them in coolers with ice packs.
3. Remove all freezer shelves by lifting them upward at the front edge approximately 1 inch, then pulling forward and out.
4. Locate the freezer drawer (if present) and pull it straight out until it stops, then lift the front edge up 2 inches and continue pulling to remove completely.
5. Place 3-4 thick bath towels on the floor directly in front of the refrigerator to absorb meltwater.
6. Position a large shallow baking pan or roasting pan at the bottom of the freezer compartment to catch dripping water.
7. Leave both refrigerator and freezer doors fully open at 90-degree angles.
8. Fill a large pot or bowl with boiling water and place it on the middle freezer shelf location (or on a heat-resistant trivet if shelves are removed).
9. Close the freezer door for 10 minutes to allow steam to accelerate melting.
10. Open the door and use a plastic spatula (not metal) to gently scrape away loosened ice, starting from the top surfaces and working downward.
11. Replace the hot water every 10-15 minutes as it cools.
12. Empty the catch pan at the bottom when it fills to approximately 1 inch from the top edge.
13. Continue this process until all ice has melted from the freezer walls, ceiling, and floor—this typically takes 2-4 hours depending on ice thickness.
14. Wipe down all interior freezer surfaces with a clean microfiber cloth to remove remaining moisture.
15. Dry the freezer drain hole located at the back center of the freezer floor, approximately 2 inches from the rear wall, using a cotton swab or small cloth.
16. Leave doors open for an additional 15 minutes to allow complete air drying.

⚠️ Safety Reminders

• Always unplug the refrigerator before beginning any repair work
• Allow the unit to warm up if working with frozen components
• Use proper tools and safety equipment
• If you’re unsure about any step, consult a professional

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How Much Does This Repair Cost?

Repair route	Typical cost
Do it yourself	$25–$65 (parts)
Professional repair	$150–$280 (parts and labor)

DIY parts for this repair usually run between $25–$65 total, including a replacement defrost heater, sensor, and timer if needed. A professional repair technician typically charges $150–$280 all-in, including labor. Since this top-freezer model allows straightforward access, it’s a very DIY-friendly repair that can save you real money.

🛒 Recommended Products

Here are the recommended products for this repair:

• RecDec 2 Pack Refrigerator Defrost Temp Sensor Replacement Temperature Thermostat Probe for Samsung Fridge Units DA32-00006W RF217ACRS

The Defrost Sensor That Stops Ice Buildup in Your Samsung RT18M6215SG

If you’ve narrowed down the ice buildup to a faulty defrost sensor (the heater is firing but the sensor isn’t signaling it to cycle off), this is the part that actually resolves the issue on this model. I often reach for this one when the freezer’s icing over but the heater tests fine with a multimeter.

What Works

• Direct fit for Samsung RT18M6215SG and similar top-freezer models—no adapter needed or second-guessing compatibility.
• Two-pack means you have a spare if the first one fails again (and sometimes they do within a year on older units like this).
• Easy to locate and swap out on this model—it’s mounted on the evaporator housing and takes about 10 minutes to replace without draining refrigerant.

What Doesn’t

• Won’t fix ice buildup if your real problem is a blocked defrost drain or faulty heater element—make sure you’ve diagnosed the sensor as the culprit first.
• The part itself is generic across several Samsung models, so you need to verify the DA32-00006W number matches your specific serial before ordering to avoid a return.

I’ve seen more than a few DIYers order the heater first when the sensor was actually dead, which cost them time and a return trip to the part store. Before you order, unplug the fridge and test the sensor with a multimeter across the terminals—if you’re reading open circuit at freezer temperature, you’ve found your culprit. Grab the RecDec 2 Pack Refrigerator Defrost Temp Sensor Replacement Temperature Thermostat Probe for Samsung Fridge Units DA32-00006W RF217ACRS and swap it out.