if you're getting 12v at the connector full time then check the ground side with the directional switch engaged.
Some machines used ground switching instead of power side switching so make sure you have ground when direction is selected and also the 12v signal on the other side of circuit.
Might want to run a resistance check on the circuit, it may read 12v but not be able to carry the load to pull the solenoid in.
Faulty connection or bad wire or switch.
Since the problem moved to the opposing solenoid that rules out any issue with the solenoid valve or control valve spool issues.