@dc42:

So the M307 H3 command isn't working, or else it is being overridden. Perhaps there is one in your config-override.g file as well? If so, delete it. If not, delete and re-type the original M307 H3 line in config.g in case it contains an unprintable character.

Ugh you're the best. I knew I was overlooking something simple…! It was overridden.

My config-override.g is as follows:

; This is a system-generated file - do not edit ; Delta parameters M665 L291.060 R144.158 H387.800 B120.0 X0.000 Y0.000 Z0.000 M666 X0.000 Y0.000 Z0.000 A0.00 B0.00 ; Heater model parameters M307 H0 A100.7 C757.4 D25.1 S1.00 B0 M307 H1 A516.8 C155.7 D2.9 S1.00 B0 M307 H2 A340.0 C140.0 D5.5 S1.00 B0 M307 H3 A340.0 C140.0 D5.5 S1.00 B0 M307 H4 A340.0 C140.0 D5.5 S1.00 B0 M307 H5 A340.0 C140.0 D5.5 S1.00 B0 M307 H6 A340.0 C140.0 D5.5 S1.00 B0 M307 H7 A340.0 C140.0 D5.5 S1.00 B0 ; Z probe parameters G31 T1 P500 X0.0 Y0.0 Z-0.05 G31 T3 P500 X0.0 Y0.0 Z0.70 G31 T4 P500 X0.0 Y0.0 Z0.00

Thank you so so much! Now I can figure the rest of this stuff out!