Pre-heating control unit

PRE-HEATING CONTROL UNIT

P3M123L01

P3M123L02

Connections

1. Earth
2. Thermal switch (NTC)
3. Ignition switch (+15)
4. Ignition switch (+50)
5. Warning light in dashboard
6. Heater plugs
7. Direct positive from battery (+30)

The graph shows two curves:

• Curve A indicates the PRE-HEATING times depending on the temperature of the engine coolant; the heater plugs are supplied and the warning light in the instrument panel is on.
• Curve B indicates the POST-HEATING times starting from the moment the engine is started; the heater plugs are supplied and the warning light in the instrument panel is off.
• The POST-HEATING stage also corresponds to a diagnostic function with which it is possible to signal faults with the coolant temperature sensor or the appropriate circuit by a warning light flashing in the instrument panel for 60 seconds.
• At the end of the POST-HEATING stage the device switches itself off.

The pre-heating should not be interrupted for engine coolant temperatures of below 80°C. The maintenance time (heater plugs supplied and warning light in instrument panel off) is 10 seconds from the moment the warning light in the instrument panel goes out.

P3M123L06