If you don't work on a lot of these units, they can be strange and mysterious beasts, even leading some techs to go insane on blind, parts-changing rampages in a vain attempt to fix a no-drying complaint.
Brethren, let us unbunch our panties and unfurl our brows while Brother john63, Dean of LG Laundry Appliantology, reveals to us the solution which, like most technical solutions, is stunningly simple once you hear it, yet ever elusive to the uninitiated:
Plan of attack as follows...
1) Remove the DUCT from the tub. Pay particular attention to the area of the duct---where it connects
to the bottom of the tub. Clean the duct system thoroughly.
2) Replace the DRAIN MOTOR (4681EA2001T)
3) Verify that the COLD WATER VALVE ASSY is the ***correct*** one. If not---replace it (5220FR2008E)
Repeat the above steps---every 3 years.
Laundry can be loaded into the tub---3/4s full.
When the laundry becomes wet during the *wash* cycle---the laundry will *sag* within the tub---to approximately 1/2 or less of the tub opening.
This will permit faster drying---than an overloaded combo unit.
Source: LG Combo Washer/dryer not drying