LG Washer Error Code 1AC7

The 1AC7 code means the upper washer main control board and the lower washer main control board have lost communication with each other. This is a dual-washer unit where two boards must continuously exchange signals to operate correctly. When those signals are not detected, the machine stops and displays this fault code. The problem most often starts at the connectors linking the two boards.

It is not recommended to continue running the washer with an active 1AC7 fault. A communication breakdown between the two main control boards means the machine cannot properly coordinate its functions, which could lead to incorrect operation or additional component damage. The unit should be diagnosed and repaired before resuming use.

A power reset may temporarily clear the 1AC7 code, but if the underlying communication fault still exists, the code will return once the machine attempts to operate. A reset is not a repair and should only be used as part of initial diagnosis to see if the fault is intermittent. The root cause in the connectors, wiring, or control boards must be addressed to permanently resolve the error.

Start by unplugging the machine and inspecting all connector connections between the upper and lower washer main PBs. Reseat any connectors that appear loose and look for signs of corrosion or damage. If the connectors are secure and undamaged, trace the wiring harness between the boards for any breaks or pinched sections. If the wiring and connectors are both in good condition, one or both of the main control boards may need to be replaced.

If the fix is simply reseating a loose connector, there may be no parts cost at all, though a service call fee would still apply if a technician performs the work. Wiring harness replacement typically runs in the range of $50 to $150 for parts. Replacing one of the main control boards is more expensive, generally ranging from $150 to $400 or more depending on the specific board and labor rates in your area.