Both fans do not run at high speed with the A/C on (but both fans run at low speed and the A/C compressor operates with the A/C on)
Diagnostic procedure
A/C pressure sensor troubleshooting: A/C pressure sensor circuit low voltage,
A/C pressure sensor circuit high voltage
ECT troubleshooting:
ECT sensor 2 circuit low voltage,
ECT sensor 2 circuit high voltage
Also check for
Powertrain DTCs
Cleanliness and tightness of all terminals