lg LDS5540ST dishwasher

[Mannymanous]

So I have an lg LDS5540ST dishwasher it's about 4-5 years old and it just displayed error code "he" which I know is the heating element. I ordered a replacement from repairclinic.com, I ohmed it out before installation and it did have continuity. I installed it ran dishwasher and still didn't work no heat,removed it checked it again and it was still good ohm wise. By the way the initial Heating Element I removed also had continuity. Called repairclinic.com and they were very good because they sent me a new one which also checked out good. I installed the new one ran it and it worked, so my wife filled it with some dishes and it failed again, removed it and it checked out with good continuity. Don't know what direction to go now, does anyone have any suggestions?

 

Thanks, Manny

[ECtoFix]

The old heating element passed your continuity test, but you replaced it anyway?  Why?

Did you do a voltage reading to the element before replacing it?  That's important.  Despite what all the wonderful videos on YouTube show, doing continuity testing of components is just ONE tool used to troubleshoot.  It's best to check voltage first, when possible.

Anyway...

I'm a commercial equipment tech, so no experience on that machine.  However, I googled your model and found a service manual on-line.  The manual has a wiring diagram.  After looking at that (and other stuff in the manual), I offer three possibilities to your problem:

• Door switch: There are actually WO microswitches that are part of the door lock assembly.  One of those switches is in series with the heating element.  Check to be sure BOTH switches close properly when the door is locked.
• Wiring & connectors: To the element.  To the door switch.  To the control PCB.  Unplug each to look at them.  Make sure all connections are clean, tight and not damaged.  Also visually inspect each of those components for damage caused by overheating.
• The main PCB: That's all there is left.  It has two relays on it to control heat.  You can't replace the relays alone.  You have to replace the board.  The service manual says a code will show if there's a problem with temperature sensing (the thermistor).  However, I'd still be inclined to test the thermistor before ultimately settling on the board being faulty.

[ECtoFix]

3 minutes ago, ECtoFix said:

Door switch: There are actually WO microswitches

That suppose to read TWO microswitches.  For some reason, this forum doesn't allow me to edit my posts.

[Mannymanous]

Thank you very much for your input I will check all of the above, I will let you know how I make out.

Thanks again, Manny