3315457 - 5040CA Check 'brushless fan 'tacho' signal to air conditioner control unit

With the ignition on and fan on, check that there is a signal (square wave) whose frequency is proportional to the engine speed and a voltage of 4-5 V varying with the engine speed (see wiring diagram).Check with a brushless motor controlled by an input signal Vc > 1.2 V, the value of the "tacho" signal (see wiring diagram).Check that the alternator output voltage is 8.8-16.0 V.