User Manual

Chapter 8
BOSCH HDI EDC 15C2 INJECTION SYSTEM AND PARTICLE FILTER
53
A - DESCRIPTION
Low speed is obtained by supplying the fan unit through a resistor arranged in
series on the supply circuit.
Mid speed is obtained by supplying the fan unit through 2 resistors arranged in
parallel in the supply circuit:
- the low speed relay is controlled by the injection ECU,
- the mid speed relay is controlled by the built-in systems interface,
- high speed is obtained by supplying the fan unit directly.
Before switching to high speed, the fan unit is operated at low speed for 3
seconds.
Before switching to mid speed, the fan unit is operated at low speed for 3
seconds (*).
(*) refer to the procedure: cooling requirements for the air conditioning (BRAC).
B - ELECTRICAL RESISTORS
SDI027C
The 2 resistors are located on the front panel, near to the air/air exchanger and
the fan unit.
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