|
From Rave, there are a few other things which will stop the heater working....
Auxiliary Coolant Pump
The auxiliary coolant pump is an electric pump that ensures there is a satisfactory flow rate through the heater matrix
at low engine speeds. The auxiliary coolant pump is installed in the engine compartment, in a rubber mounting
attached to the side of the LH suspension turret. Operation of the auxiliary coolant pump is controlled by a power
supply from the ATC ECU.
Coolant Valve
The coolant valve controls the coolant flow to the heater matrix. A single coolant valve controls the coolant flow to
both sides of the heater matrix on low line systems. On high line systems, separate coolant valves control the coolant
flow to each side of the heater matrix. The coolant valves are installed in the engine compartment on a bracket
attached to the side of the LH suspension turret.
Each coolant valve is a normally open solenoid valve controlled by a Pulse Width Modulated (PWM) signal from the
ATC ECU. The ATC ECU changes the length of time the coolant valve is open each duty cycle between 0 second
(valve closed) and 3.6 seconds (valve held open). On the high line system, the PWM signals to the two valves are
phase offset by 1.8 seconds to reduce coolant flow fluctuations.
Heater Matrix Temperature Sensor
The heater matrix temperature sensor is a NTC thermistor that provides the ATC ECU with a temperature signal from
the air outlet side of the heater matrix. On low line systems, a single sensor is installed in the rear of the heater
assembly casing, to the right of the centre-line. On high line systems, two sensors are installed, one each side of the
centre-line.
The ATC ECU uses the input from the heater matrix temperature sensor(s) to control the operation of the coolant
valve(s).
The signal voltage from each heater matrix temperature sensor is between 0 and 5 V. The ATC ECU monitors the
signal voltage and defaults to a temperature of 55 °C (131 °F) if it goes out of the range 0.173 – 4.890 V:
l If the signal voltage is less than 0.173 V, the ATC ECU assumes there is a short circuit to ground
l If the signal voltage is more than 4.890 V, the ATC ECU assumes there is an open circuit or a short circuit to
battery
Sunlight Sensor
The sunlight sensor consists of two photoelectric cells that provide the ATC ECU with inputs of light intensity, one as
sensed coming from the left of the vehicle and one as sensed coming from the right. The inputs are a measure of the
solar heating effect on vehicle occupants and used by the ATC ECU to adjust blower speed, temperature and
distribution to improve comfort. The sensor is installed in the centre of the fascia upper surface.
If one of the photoelectric cells is faulty, the output from the other photoelectric cell is used for both sides of the vehicle.
If both photoelectric cells are faulty, the ATC ECU uses a default value of zero. Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-
|
20th Oct 2014 11:01pm
