LG HE error, but no problem with the heating element

[jamesvenning]

Hi all,
I have an LG dishwasher model LD1452. At the end of the cycle, it displays at HE error, even though the dishes feel warm. I have checked the resistance across the heating element according to the service manual, and it measured about 30 ohms. I have then pulled the front cover off and checked the resistance across X1 and X2 relays, but seems no connectivity. The manual suggests to do this “with the door closed” – does this mean I need to do something to the door open sensor? I am also assuming the unit is meant to be off during all these checks. Can anyone advise the next steps from here?
Cheers,
James

[electrofix]

I don’t know this unit and not seen the workshop manual but cant see what they are getting at

for the heater to come on a few things have got to be in place
1 the heater has to work
2 the temp sensor has to call for heat
3 the water level sensor and or the water flow sensor has to confirm its ok to turn the heater on
4 relays have to close to turn it on

the relays they are asking you to check will not be energised with the power off and you cant make resistance reading with the power on

so it makes no sense

Dave

[electrofix]

well if you look at the picture where they are measuring and the wiring diag. from what I can see it shows a check on continuity between the brown and blue wires on the relays

looking at the diagram is shows a joint between the 2 in the wiring harness

so if you are not getting continuity between these 2 it needs investigating

Dave

[electrofix]

wait a minute that diagram is wrong it cant work heater has no return cable

right had a re think

try this

start dishwasher and wait till its full of water and washing

then unplug and try the test

what I think is going on it this

to enable the heater to come on several safety protocols are in place

1 pressure switches both pressure switch 1 and 2 have to be activated
2 door switch has to be closed. there seems to be a double door switch where one is just for the heater

Dave

[electrofix]

right figured it correct diagram should be

Dave

so now you can see with the dishwasher full and the door closed you should read the heater element across the 2 connection. if you don’t get it you need to trace the circuit one component at a time. I would check door switch first as it should be easy to access

D

[jamesvenning]

Excellent! Will give it a go. Thank you!!

[jamesvenning]

Hi Dave,
Working through the diagram, there was an open circuit across the pressure switches, even though the dishwasher was full of water. I pulled the PS out, and it looked pretty clogged. After cleaning, I can blow into the pipe and I hear the diaphragm click and the circuit closes.

When I reassembled everything, I ran a load and it stopped a few minutes in with an OE error (I’m assuming I didn’t connect something properly when I reassembled it – I can’t hear the drain motor start up, although I can’t see anything obviously disconnected or kinked) BUT, when I repeat the test that you suggested, I still don’t get a closed circuit across the pressure switches. So it seems I have developed another problem without first fixing it. Or, would the OE error prevent me from properly diagnosing the initial problem with the pressure switch?

[jamesvenning]

Hi Dave,
Got it working! Not sure about the OE error, but the inlet to the pressure switch was all blocked up. When I put everything back together, it worked fine. Thanks for your help!

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