WM3431HS - dHE Error (cleaned trap, etc)

[john63]

6 minutes ago, moore1289 said:

The blower wheel definitely spins, so that is not the issue.

 

When the blower motor is installed...it runs?

[moore1289]

Yes, blower motor has always run. The heater does not turn on when blower motor is installed, but the blower motor does run.  

[moore1289]

Continuity is perfect for all 3 wires to the main board.  There is a yellow connector on the main board that the wires go directly to.

 

Could this be a grounding issue of some kind?

[moore1289]

Forgot to mention that I did the test mode with me holding the dryer blower in my hands up right, and it made no difference.  Blower fan starts up and runs and yet no power goes to heater.

[john63]

Ok blower runs...I had the incorrect impression that it failed to run when installed.

But...it is the heater that is not coming on...when the blower is installed.

Gonna re-read this entire thread again...then we'll try a few things...

[john63]

3 minutes ago, moore1289 said:

Forgot to mention that I did the test mode with me holding the dryer blower in my hands up right, and it made no difference.  Blower fan starts up and runs and yet no power goes to heater.

Got it.

[john63]

On 4/16/2017 at 6:50 PM, moore1289 said:

The dHE error comes on about 8-19 minutes into the drying cycle. 

Ok...has the rear (white plastic) duct been removed and cleaned?

Also the entry hole at the bottom of the tub...where the duct attaches to...has that been inspected for a blob of lint restricting airflow?

[moore1289]

Yes, the condensing duct has been completely removed, and completely cleaned.  There isn't a spec of lint in there.  Also the entry duct on the back where it connects has been completely cleaned, in as far as I could reach.

[john63]

Good...that removes airflow as an issue altogether.

Unplug combo...remove both wires from the Thermostat (on left side of black duct housing) and bypass by attaching those 2 wires...wrap with electrical tape.

Plug in unit and run test mode 11 again...this will eliminate a potential weak thermostat that fails under load.

[moore1289]

removed thermostat from circuit by connecting wires.  No change.  Heater is still cold during test cycle.

[john63]

Test voltage at heating element with your meter.

If you have a meter that can test electrical load...even better.

120 volts AC?

[moore1289]

There is no voltage at the heating element.  The only time the heater gets power is when the blower was turned upside down during test mode.

 

Voltage is measured across the two contacts of the heating element, correct?  Ive tested the heater and it works.  

[john63]

Checking wiring schematic...

[john63]

On the Main Board...there's a red plug with 3 wires on it (blue...yellow...and red).

In test mode 11...test for 120 volts from the blue wire at the *Main Board* to ground.

If 120 volts...test for 120 volts at *heater connector*...blue wire to ground.

Note:

If no voltage at Heater...

Unplug washer combo...disconnect blue wire from *Heater* and pull red plug connector off *Main Board*...test for continuity of blue wire from Main Board plug/blue wire to Heater blue wire connector. 

If "open"...need new Wire Harness (a rare failure...never had that before).

Additional...

Both Thermistors are plugged in/connected?

Both Thermistors show 39.5k ohms at 86 degrees F ?

Thermostat on blower housing shows continuity (closed)?  *Remove power plug prior to testing*

Heater resistance is within 10 to 40 ohms ?  *Remove power plug prior to testing*

Fuse in heater housing has continuity? *Remove power plug prior to testing*

[moore1289]

OK, let me check those in the morning.  In the meantime, here is the actual wiring diagram.(https://drive.google.com/file/d/0B1FvVyLL8yyMc2E1Sml5bEhabkk/view?usp=sharing)  The one in the service manual is incorrect.

[Budget Appliance Repair]

I've never worked on these so just going from what I have read.

If I have read every thing correctly - the current situation is if you pull the blower motor out and turn it upside down, (I have no idea what the motor looks like - but I assume this would mean the blower wheel is pointed straight up and facing you), the motor runs and the heater turns on.   Then if you flip the motor with blower wheel pointing face down the way it would be installed in the machine the blower wheel still runs but no heat.

Maybe when in correct assembled position the motor is actually running slower but not enough to tell by eye but rpm slow enough to not satisfy the controls required rpm to turn on heater.

Shaft could be gummed up in normal position then when turned upside down the rotor moves the shaft to a cleaner position where it can turn at normal speed?

[moore1289]

I thought the same thing.  I bought another blower assembly and both do the same thing when installed, which leads me to rule out that assembly as bad.  Very strange though, I really cannot figure out this problem.

[moore1289]

On the Main Board...there's a red plug with 3 wires on it (blue...yellow...and red). I believe this schematic is based off repair manual and is not correct.  Mine has a White connector with a BL and BK wire.  BL has 120V in Test 11 mode.

In test mode 11...test for 120 volts from the blue wire at the *Main Board* to ground. Yes 120 V

If 120 volts...test for 120 volts at *heater connector*...blue wire to ground. Yes 120 V, however heater is not getting hot.  I have 2 heaters now, and both test as good, and when plugged into wall outlet independently, both turn on and get hot. Note, the one installed is brand new.

Note:

If no voltage at Heater...

Unplug washer combo...disconnect blue wire from *Heater* and pull red plug connector off *Main Board*...test for continuity of blue wire from Main Board plug/blue wire to Heater blue wire connector.

If "open"...need new Wire Harness (a rare failure...never had that before).

Additional...

Both Thermistors are plugged in/connected? Yes

Both Thermistors show 39.5k ohms at 86 degrees F ? Both read about 42.8k ohms, but its more like 70F, don’t know how to do this test at 86F.

Thermostat on blower housing shows continuity (closed)?  *Remove power plug prior to testing* YES

Heater resistance is within 10 to 40 ohms ?  *Remove power plug prior to testing* YES 11.3 ohms

Fuse in heater housing has continuity? *Remove power plug prior to testing*YES

 

Also previous test where flipping fan over and heat turns on, no longer works...

[john63]

A tough one to diagnose!

I'll keep brainstorming...

[moore1289]

Do you know of any other tests or sensors that the main board is looking at in order it to send power to the dry heater (or pull the power to neutral).  There is some sort of fault or sensor that would cause it to not want to send power to heater.

[john63]

If I had this combo on a service call or at our shop...

I'd be tempted to experiment (not saying that you should though).

Here's what I'm thinking...

Unplug combo.

Get 3 long strips on test wire...the same color as the wiring on the blower motor.

Insert all 3 into plug at main board connector.

Insert all 3 wires at the blower motor connector.

Plug in combo and test.

 

 

 

Edited April 23, 2017 by john63

[moore1289]

Well I've got an extra blower motor, so why not.

[Budget Appliance Repair]

Really sounds like a broken feedback wire from the blower fan motor since it has now quit working even when turned up towards you.

Have you ohm'ed out all three wires from the connector the goes into the control board down to the connector at the blower motor, (the wire can be broken inside the plastic wire sheathing and you won't know it by just looking).  I would be concentrating mainly on the feedback wire since the motor runs the other two wires would have to be OK.

 

[moore1289]

OK, I soldered a completely new set of 3 wires from blower to main board and it didn't change anything   Was really hoping that would fix things... You guys have any other ideas?  Would having a LG repair guy come out be worth anything? Seems I am low on options.

[john63]

I'm running on fumes too.

1) Part numbers on original Main Board and replacement...identical?

2) Power outlet (on wall) tested okay...ground good?

3) Combo unit has plenty of air? Not installed in an airtight closet with a door?