I have an LG DLE5977W electric dryer It
runs fine but doesn't heat up. When running, the "Dry" light flashes and the "Cooling" light stays lit.

I have tested the following components:
Thermal Fuse: 0/.1 ohm
High limit thermostat: 0/.1 ohm
Themostat (blower unit): 0 ohm
Thermistor (blower unit): 12k ohms (when not running)
Heating Element: Red/Blue: 19.9 ohms; Red/Yellow: 19.9 ohms; Blue/Yellow: 40.0 ohms

I replaced the thermistor since it wasn't always giving me a consistent reading, but that didn't fix it.

I'm getting 110vac on each leg and off the motor assembly, and I know the 220 outlet is good.

In diagnostic mode, I get the following code: 18:F0 / U01.

I replaced the Main Control Board, figuring it was the only thing left. But that didn't work either

What else can I check?