Author Topic: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?  (Read 3608 times)

Offline Volvoman

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LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« on: January 04, 2011, 08:57:28 AM »
I have a LDF8812ST. I think that the motor is bad.

All volts taken in test mode
I have +12 VDC coming to the motor from the red and black wires. +9.9 VDC from Black to Gray and +9.9 VDC Black to Purple.
 Other readings:
 Black to Light Blue .64 VDC
Black to Dark Blue .95 VDC
Black to White 1.4 VDC

Also the motor shows an open (Infinite resistance or OL) through all pins and to ground. The motor has rusty looking stuff and a faint burnt smell coming from the bottom of the motor in one of the vents where you can see the motor windings.

The motor says 340VDC. Are these Motors in fact DC?
Is the voltage reading that I have provided in the correct range to say that it is the motor?
Is the rusty stuff normal or an indication of Motor failure?

Thanks,

Chuck

Offline tgoods

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Re: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« Reply #1 on: January 04, 2011, 09:09:23 AM »
If the windings are open then the motor is bad.  This is an electronically commutated DC motor.  Most meters would not be able to get an accurate voltage reading at the motor.

Offline Volvoman

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Re: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« Reply #2 on: January 04, 2011, 10:31:32 AM »
So this is a DC motor. Very strange! What should the voltage read? I have already checked for continuity but which pins are power inputs to check for continuity? Red, Blue and Purple are all power inputs? Does this sound like a bad motor to you.

Chuck

Offline JWWebster

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Re: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« Reply #3 on: January 04, 2011, 11:44:30 AM »
Chuck here is a typical LG dw manual LG DISHWASHER SERVICE MANUAL

Don't forget to hunt for a cut wire in that black goop:
A previous asker wrote: Before calling for service (LG LDF6810xx) for the dreaded LE error code we checked the wiring in the door per this thread. Sure enough a black wire completely broken in half and a red one with the insulation off. The black wire was completely embedded in the sound deadening material such that it was hard to even spot it at first.Anyway, simple fix and lots of money saved. Thanks to all.
« Last Edit: January 04, 2011, 11:56:08 AM by JWWebster »
May the hinges of our friendship
        never grow rusty.

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Offline Volvoman

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Re: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« Reply #4 on: January 04, 2011, 12:03:33 PM »
JW,
 I have already checked for broken wires. I also did not see any black goop that everyone talks about on this model. The wiring harness runs through a white plastic loom. No cheap wire fixes here.
Thanks for the advice! Chuck

Offline JWWebster

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Re: LG Dishwasher Motor Trouble shooting. Motor is 12 VDC?
« Reply #5 on: January 04, 2011, 12:54:06 PM »
Problem: What is the correct part number for the motor/sump assm. Ive seen updated and improved part numbers and I want to make sure I get the best one.

Solution: As of this posting---all LG dishwashers (2004-2010) use the same SUMP ASSEMBLY.
p/n: AJH31248604.




Note: The AJH31248604 Sump Assy replaces all
previous Sump Assemblies.
THESE WERE THE WASH MOTOR FAILURE SUMPS
6871DD1002A
6871DD1002B
May the hinges of our friendship
        never grow rusty.

About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack. The small green square=personal message. The green dot is a link to my web page on appliance repair and other general BS I love to post. The letter sends me email.
I love fan letters! LOL

 

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