This signal is sent to the control unit when there is a need for the electrical circuits of the air conditioner (air conditioner switch).
Start the engine.
Turn on the compressor.
Turn on the air conditioner (air conditioner switch).
If the air conditioner does not work, then it should be checked.
If the air conditioner is working, then you should measure the voltage between 10 (Blue/Red (+)) and 32 (black (-)) contacts.
If the voltage is below 3 V, then the air conditioner switch signal is normal.
Otherwise, repair the break in the Blue/Red wire between the A/C switch and terminal 10 of the control unit.