Functional Description

Functional Description

Heater fan:

The heater fan Q1 is supplied with battery voltage through the key-operated services relay I35 - located in fusebox G1 -; in addition to the relay, the supply line also crosses fuse F13 of fusebox G1.

The fan motor Q1 is operated with an earth signal from the control knob Q4. This signal crosses the speed regulator Q5, comprising three resistances in series, the crossing of which determines the four different speeds, depending on the signal from the knob Q4: from pin 2 of connector B (1st speed), from pin 1 of connector B (2nd speed), from pin C of connector A (3rd speed ) and lastly from pin B of connector A (4th speed) with a direct signal that does not cross the regulator Q5.

The regulator Q5 has a built-in thermal safety fuse that deactivates the circuit for temperatures above 98°C.

Recirculation:

The recirculation function is operated by the motor Q27, according to the following logic:

• pin 2 of Q27 always earthed;
• 12 V at pin 3 of Q27: the motor turns cutting in recirculation;
• 12 V at pin 1 of Q27: the motor turns cutting out recirculation;
• Cutting in takes place via switch B98, but with switch Q4 on "0", "1", etc...:
  • switch B98 not pressed: recirculation not operational;
  • switch B98 pressed: recirculation operational.

N.B. : With switch Q4 at "OFF" recirculation is still engaged regardless of the position of switch B98

Controls lighting:

Lights F8a and F8b, inside the control panel, together with the leds next to switch B98 are supplied by the sidelights circuit - connector D of fusebox G1 (also see "Lighting of controls and indicators").