Functional Description

Functional Description

The delaying device Q42 located in group Q41 controls the cutting-in of the electric fan to improve the cooling of the air conditioning system compressor.

The key-operated voltage supplies the coil and the electronic devices of the delay system Q42 -pin 85 (from chassis N... the "key-operated" supply come from the line of fuse F15 (10A) of G1); the coil is excited by an ground signal -pin P- which can come from either the

trinary pressure switch Q20, or from level 1 (87-92°C) of the two-stage thermocontact L33: this causes an ground signal to be sent - pin 30- to the additional resistance O22 and from there to the electric engine cooling fan P2, which is then operated at the 1st speed.

The electric fan P2 is constantly supplied by battery voltage through the special fuse, G254 (40A).

After about 10 seconds, if the control signal persists, or if level 2 of thermo-

contact L33 is reached (92-97°C), the delay device Q42 sends -pin 86- an ground signal which excites the coil of the fan relay 11, and actuates the fan itself P2 at the 2nd speed.

Starting from chassis N... the layout of the air conditioner wiring has been changed with modification of the connections only as described above.