Whirlpool Dryer WED9400SW0 - overheating

[BB430]

Hi, I am troubleshooting my electric dryer that won't stop heating, even on Air Only.

Main question now is: On machine control electronics board, what is "normal" resistance between P4-3 and P4-6?

Background:  Dryer got clothes fiery hot, so I got in and cleaned out the moderate amount of lint/dust, and also replaced the thermistor and thermal fuse, which were bad. I tested the continuity of the heating element (resistance was 10 ohms). I didn't remove the heating element housing, but I can see clear into it and sure looks like no part of the element is touching walls of housing (grounded.) Tested the continuity of thermostat/thermal cutoff (both read about 0.3, which is also what I get when I touch my new multimeter leads together, so I assume that's "zero.") Then tested the thermal cutoff (part #8557403) on a griddle, and it didn't cut off even at 250, while it has L146 on sticker. Figured that was the problem, replaced thermostat and thermal cutoff. Still overheating on Air Only. Tech sheet said to get into machine control electronics and test resistance between P4-3 and P4-6. It says that between 5-15k ohms means replace control board, over 20k replace thermistor. But I'm getting 18.8k ohms -- right in between! Is that just "normal"?  Any idea how to proceed? Thank you so much.

[micabay]

 A.   The "hard" but 100% way= Check the heat relay, should be open (O.L)  when dryer is off and unplugged.  Also check the heater element for grounding out.    

B.   The "Easy" most likley but not 100% way is a visual check=  With only the lower panel off, run the dryer on airfluff.  The heater should not be heating under normal operation, you state that it still heats.  Is the heater fully glowing?  or only half  the coils glowing?  

      1.  Fully= most likely heat relay on control is stuck closed.  Replace control

      2. Half or partial glowing= heater is shorting out.  Replace heater, and check your venting.  Poor airflow can cause a heater to short.

Part number: AP6015062

Part number: AP6013115

[BB430]

It was indeed the heat relay -- it was totally scorched and fused closed. Will be replacing the whole control board.  Thank you!