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

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! Any idea how to proceed? Thank you so much.