LG LMX25981ST Service Manual

The LG LMX25981ST is a high-performance appliance requiring specialized service procedures. This manual provides authorized service technicians with essential information for installation, troubleshooting, repair, and maintenance. It includes safety warnings, technical specifications, disassembly/assembly instructions, wiring diagrams, and parts lists. Use this manual in conjunction with proper tools and training to ensure safe and effective service.

1. Safety Precautions 2. Product Specifications 3. Installation Instructions 4. Operational Overview 5. Disassembly Procedures 6. Electrical System 7. Component Testing 8. Troubleshooting Guide 9. Parts List & Exploded Views 10. Reassembly & Verification 11. Warranty & Service Information

Safety Precautions

Before servicing, read all safety instructions. Disconnect power before accessing internal components.

HazardPrecaution
Electrical ShockUnplug unit or disconnect power at circuit breaker. Verify with voltage tester.
Sharp EdgesWear cut-resistant gloves when handling internal components.
Hot SurfacesAllow unit to cool completely before disassembly.
Heavy PartsUse proper lifting techniques; get assistance for heavy components.
Refrigerant (if applicable)Only EPA-certified technicians may handle refrigerant lines.

WARNING! Failure to follow safety procedures may result in injury, death, or product damage.

Product Specifications

Installation Instructions

Proper installation is critical for performance and safety.

  1. Site Preparation: Ensure level, stable floor. Verify electrical outlet meets specifications.
  2. Unpacking: Remove all packaging materials and transit bolts (if present).
  3. Positioning: Move unit into final location using appropriate equipment. Do not tilt beyond 45 degrees.
  4. Connection: Plug into dedicated grounded outlet. For hardwired models, follow local electrical codes.
  5. Leveling: Adjust front leveling legs. Use a spirit level.
  6. Final Check: Ensure no kinks in hoses or lines (if applicable). Open doors to check alignment.

CAUTION! Installation by qualified personnel only. Improper installation voids warranty.

Operational Overview

Understanding normal operation aids in diagnosis.

Control Panel: Describes buttons, indicators, and display symbols. Standard Cycle: Sequence of events (e.g., fill, heat, wash, drain, dry). Error Codes: List of common display codes and their meanings (e.g., F1, F5, LE).

Disassembly Procedures

Step-by-step guide to access internal components. Perform in order.

  1. External Covers: Remove rear service panel screws. Detach top panel by releasing clips.
  2. Control Panel: Disconnect wiring harnesses. Note connector positions.
  3. Internal Access: Remove front lower panel. Access door switch and latch mechanism.
  4. Major Components: Procedures for removing motor, pump, heating element, or control board.

Tip: Take photos during disassembly and bag/organize all screws.

Electrical System

Wiring diagrams and schematic located in appendix. Key electrical components:

ComponentFunctionTest Point/Resistance
Main Control BoardGoverns all cycles and inputs.Check for 5V/12V DC at regulator.
Door Lock SwitchSafety interlock.Continuity check when latched.
Heating ElementHeats water/air.Measure resistance (typically 10-50 Ω).
Motor/WindingsDrives drum/pump.Check for shorts/opens between phases.
Thermal Fuse/CutoffOverheat protection.Continuity check.

Component Testing

Use multimeter to verify component functionality before replacement.

  1. Sensor Testing: (e.g., Thermistor, Pressure Switch) - Measure resistance across terminals at known temperatures/pressures. Compare to chart in manual.
  2. Switch Testing: (e.g., Door Switch, Water Level) - Check for continuity in activated vs. deactivated state.
  3. Motor Testing: Disconnect power. Check windings for continuity and absence of short to ground.
  4. Control Board Inputs: Simulate sensor signals to verify board response.

Troubleshooting Guide

Symptom / Error CodePossible CauseCorrective Action
No Power / No DisplayPower cord, outlet, main fuse, control board.Verify outlet power. Check continuity of power cord. Test/replace main fuse on control board.
Will Not Start / Door Lock ErrorDoor not closed properly, faulty door latch/lock switch, wiring.Inspect door alignment. Test door lock switch continuity. Check harness for damage.
No Heat / UnderheatingHeating element, thermal fuse, thermostat, control board relay.Test heating element resistance. Check thermal fuse for continuity. Verify control signal to heater relay.
Excessive Noise / VibrationUnlevel unit, foreign object, worn motor bearings, loose components.Re-level unit. Inspect drum for obstructions. Check motor mounts and bearings.
Water LeakageLoose hose connections, damaged tub seal, clogged drain pump filter.Tighten all hose clamps. Inspect door boot/tub seal. Clean drain pump filter.
Fault Code [e.g., F5]Motor control fault, tachometer error, blocked drain.Clear drain line. Check motor wiring and hall sensor. Test motor control module.

Parts List & Exploded Views

Reference diagrams [Diagram A, B, C] for part locations. Key replacement parts include:

Note: Always use genuine LG parts for repair. Part numbers subject to change.

Reassembly & Verification

  1. Reverse disassembly steps. Ensure all connectors are fully seated and routed away from moving parts.
  2. Secure all panels and screws. Do not overtighten.
  3. Pre-Power Check: Visually inspect for loose tools, wires, or parts.
  4. Power On Test: Restore power. Run a diagnostic cycle or short test cycle.
  5. Functional Test: Verify all modes operate correctly. Check for leaks, unusual noises, and error codes.
  6. Final Inspection: Confirm door seals properly, controls are responsive, and unit is level.

Warranty & Service Information

Warranty: LG standard limited warranty applies. Unauthorized repairs may void warranty. Keep proof of purchase.

Service Contacts:
LG Customer Support: 1-800-243-0000
LG Service Website: www.lg.com/us/support
Authorized Parts Distributor: 1-888-542-2623

Manual Revision: 1.0
Publication Date: [Date]
© LG Electronics. All rights reserved.

LG LMX25981ST Service Manual © - All Rights Reserved 2025