Home > Technical (L322) > In Car HEATER - PROBLEM |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
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21st May 2017 5:56pm |
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Joe90 Member Since: 29 Apr 2010 Location: Hampshire Posts: 6407 |
It is just not cold enough inside or outside of the car?
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21st May 2017 6:52pm |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
Hey Joe 90
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22nd May 2017 7:52am |
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Dolphinboy Member Since: 07 Dec 2009 Location: Bristol Posts: 3136 |
1. Poss air block in coolant system into heater matrix.
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22nd May 2017 8:51am |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
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22nd May 2017 10:36am |
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rodp Member Since: 09 Apr 2017 Location: The Black Country Posts: 318 |
So does my younger brother, and I wouldn't trust him with a chocolate spanner let alone real tools |
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22nd May 2017 6:54pm |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
not worth belonging too |
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22nd May 2017 7:38pm |
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Highroller Member Since: 18 Jul 2016 Location: Hampshire Posts: 565 |
Hi EmiratesA380
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22nd May 2017 8:30pm |
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rodp Member Since: 09 Apr 2017 Location: The Black Country Posts: 318 |
Well you've lost me on that one I must admit. And I shall say hello to my son in just a few short weeks. And as for my brother, well it's some sort of Airbus, they're all the same to me, big tubes with wings flown by computers Tesco's ???? |
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22nd May 2017 9:33pm |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
[quote="Highroller"]Hi EmiratesA380
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23rd May 2017 8:07am |
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Weegie Member Since: 09 Jun 2014 Location: East Sussex Posts: 3233 |
This may not apply to later models but, according to the owners' manual, Auto should be used:
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23rd May 2017 10:41am |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
Weegie
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23rd May 2017 11:08am |
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EmiratesA380 Member Since: 14 Jan 2015 Location: england Posts: 350 |
Here we go HiRoller Hope this help you also: OVERVIEW The air conditioning (A/C) control system automatically adjusts the temperature, volume and distribution of the air from the heater to maintain the individual temperature levels selected for the left-hand (LH) and right-hand (RH) sides of the cabin. The system also has manual overrides for the intake air source, blower speed and air distribution. Some vehicles may be fitted with a 4 zone climate control system. ATC MODULE The ATC module is installed in the center of the instrument panel. An integral control panel contains push switches and rotary switches/knobs for system control inputs. Orange tell-tale light emitting diode (LED)s in the switches and switch surrounds illuminate to indicate the current settings of the system. The rotary temperature switch is graduated in degrees Celsius, except on USA vehicles, where it is graduated in degrees Fahrenheit. An in-vehicle temperature sensor and associated electric fan are installed behind a grille in the control panel. The ATC module processes inputs from the control panel switches and system sensors, then outputs the appropriate signals to control the A/C system. In addition to controlling the A/C system, the ATC module also controls the following: The heated windshield and windshield wiper parking area heater (optional fit, not available on vehicles with infra red protection glass). The windshield washer jet heaters. The heated rear window. The front seat heaters. LH and RH Temperature Switches Adjusts the nominal temperature settings of the LH and RH sides of the cabin between 16 and 28 °C (60 and 84 °F). The temperature range is engraved on the switch surrounds. A pointer on each switch indicates the selected temperature. In the minimum and maximum temperature positions, the system operates at maximum cooling or maximum heating respectively. Automatic Mode Switch Activates the automatic modes for air volume and distribution and also activates the A/C compressor. Separate LEDs in the automatic mode switch illuminate when the blower and the distribution control doors are in automatic mode. Manually selecting the blower speed or a distribution switch extinguishes the related LED. Inputs and Outputs Five electrical connectors provide the interface between the ATC module and the vehicle/heater assembly wiring. The ATC (automatic temperature control) receives all information from EMS via BCM. If the signal is CAN (controller area network) based and it has an associated QF (Quality Factor), then this is what will be stored in RAM (random access memory), so that it will be possible to log via CCP. If the signal is CAN based and lacking a QF, or if the signal is hardwired, then the HVAC s/w must determine the applicable QF value and report this via diagnostics or CCP when requested. If a fault develops and QF = 0 at start up, then the evaporator sensor signal is used until QF >= 2. If evaporator temperature sensor is faulty, then a default of 10oC will be used until either sensor QF >= 2. If ambient temperature sensor QF >= 2 at start up, then during session QF drops to <2>= 2 again. IN-VEHICLE TEMPERATURE SENSOR The in-vehicle temperature sensor is an encapsulated negative temperature coefficient (NTC) thermistor that provides the ATC module with an input of cabin air temperature. The in-vehicle temperature sensor is installed behind a grille in the ATC module control panel. An electric fan in the ATC module runs, to draw air through the grille and across the in-vehicle temperature sensor based on: If MSCAN-Bus inactiv/active then Fan on for 300sec, then switch off. If Power mode changes to 4, then Fan on for 300sec then fan off. If Power mode changes to 6 and HVAC on, then Fan is on. If Power mode changes to 6 and HVAC off, then Fan on for 15sec, then fan off. If fan off, then fan requested to be on, then Wait x sec before fan on. If Power mode 7, then: Fan on regardless of HVAC on/off status. Fan is not disabled during crank (Power mode 9) The ATC module uses the signal from the in-vehicle temperature sensor for control of the coolant temperature valve(s), blower speed and air distribution. The signal voltage from the in-vehicle temperature sensor is between 0 and 5 V. The ATC module monitors the signal voltage and defaults to a temperature of 20 °C (68 °F) if it goes out of the range 0.4 - 4.8 V: If the signal voltage is less than 0.4 V, the ATC module assumes there is a short circuit to ground. If the signal voltage is more than 4.8 V, the ATC module assumes there is an open circuit or a short circuit to battery. The signal voltage from the evaporator temperature sensor is between 0 and 5 V. The ATC module monitors the signal voltage and defaults to a temperature of 0 °C (32 °F) if it goes out of the range 0.157 - 4.784 V: If the signal voltage is less than 0.157 V, the ATC module assumes there is a short circuit to ground. If the signal voltage is more than 4.784 V, the ATC module assumes there is an open circuit or a short circuit to battery. HEATER TEMPERATURE SENSOR The heater temperature sensor is a NTC thermistor that provides the ATC module with a temperature signal from the air outlet side of the heater core. Two sensors are installed, one each side of the vehicle center-line. The ATC module uses the input from the heater temperature sensors to control the operation of the coolant valves. The signal voltage from each heater temperature sensor is between 0 and 5 V. The ATC module 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: If the signal voltage is less than 0.173 V, the ATC module assumes there is a short circuit to ground If the signal voltage is more than 4.890 V, the ATC module assumes there is an open circuit or a short circuit to battery. AUXILIARY COOLANT PUMP The auxiliary coolant pump is an electric pump that ensures there is a satisfactory flow rate through the heater core 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 module. PRINCIPLES OF OPERATION The system operates on the reheat principle. Air entering the heater assembly is cooled to a constant value by the evaporator and then reheated as necessary by the heater core to produce the temperature(s) selected on the control panel. To determine the various system settings, the ATC module derives a reference value (called the Y factor) from: The temperature setting on the control panel. The ambient temperature. The in-vehicle temperature. The reference value is measured in %, where -27.5% means maximum cooling is required and 100% means maximum heating is required. Separate reference values are produced for the LH and RH sides of the heater assembly. The reference value is used for temperature control. The driver's side reference value is also used for door positioning and blower speed calculations. When the ignition is turned off the ATC module memorizes the system settings and resumes the same settings the next time the ignition is switched on. Temperature Control To determine the amount of heat required, in the form of coolant flow through the heater, the ATC module compares the reference value with the heater temperature and incorporates a correction factor to compensate for changes of coolant flow rate with engine speed. From the resultant value the ATC module determines the open duration of the coolant valve and outputs the appropriate control signal. On the automatic system, separate values and output signals are generated for each coolant valve to produce the individual temperature control for the LH and RH sides of the cabin. When the temperature setting on the control panel is set to maximum, the ATC module signals the coolant valve to remain open. When the temperature setting on the control panel is set to minimum, the ATC module signals the coolant valve to remain closed. On the automatic system, the minimum setting is over-ridden when the defrost program, maximum A/C, rest heating or fuel fired booster heater functions are selected. Maximum A/C Pressing the maximum A/C switch while the engine is running and the ambient temperature is more than 7 °C (45 °F) provides the maximum cooling possible from the system to cool the cabin down as rapidly as possible. When maximum A/C is selected the coolant valves are held closed, the A/C compressor is engaged, the blower speed is set to maximum and the recirculation doors are set to the recirculation position. After 12 minutes the recirculation doors will be set to fresh air for 1 minute then returned to the recirculation position. The maximum A/C function is cancelled when any of the other A/C system switches are pressed. Rest Heating When the engine is not running, pressing the maximum A/C switch activates the rest heating function to heat the cabin with residual heat from the engine. The rest heating function activates provided the following conditions exist: It is less than 2 minutes since the ignition was selected off. Ambient temperature is less than 15 °C (59 °F). On the previous ignition cycle engine temperature exceeded 70 °C (158 °F). Battery voltage is 11.4 V minimum. To provide the rest heating function, the ATC module activates the auxiliary coolant pump, coolant valves, control door and blower. The ATC module regulates the temperature (to the driver setting selected before the ignition was switched off), opens the face level distribution doors and runs the blower at speed 4. The rest heating function is cancelled after 15 minutes or when The maximum A/C switch is pressed again. The ignition is selected on. Battery voltage decreases to less than 11 V. So in a nut sheel I am going to get to the bottom of this - Hope this helps you too - Hi Roller .. |
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23rd May 2017 11:49am |
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Highroller Member Since: 18 Jul 2016 Location: Hampshire Posts: 565 |
Great info, I didn't realise that there were so many sensors.
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23rd May 2017 4:32pm |
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