Heater Temp Sensor position
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No you are not going mad. On the cooling system diagrams the hoses go to the correct pipe. But they fail to show the metal pipes connections to the matrix properly.
ovalandrover
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I dont think the heat sensor position will affect the air con first check the refrigerant level in the air con system.
The Heater Matrix inlet temp sensor might have a say as its in the air-con section in RAVE and in the air-con Control system components list seen underneath.
Read somewhere that air-con may engage even with low refrigerant level if both temp settings are set to LO worth a try... Free
Few useful things here:Range Rover P38 Maintenance repair improvements and tips learned by experience by ownership.
From Rave:
The control system operates the refrigerant system
and the control flaps in the heater unit to control the
temperature and distribution of air in the vehicle
interior. It also outputs signals to the fresh/
recirculated air servos and the blowers to control the
volume and source of inlet air. The control system
consists of:
An Air Temperature Control (ATC) ECU.
An in-car temperature sensor.
An ambient air temperature sensor.
An evaporator temperature sensor.
A heater coolant temperature sensor.
A sunlight sensor.
A dual pressure switch.
A single pressure switch.
I was running without the temp sensor working for a while. Heating fans used to take ages to come on when in auto, now they ramp up slowly and come on when the system gets hot. My outside temperature sensor is knackered because it reads low -40. Then sometimes ok. So need to change that too. Quite a clever aircon system, all the senders have an effect on how the system blows air at you.
I still have to do the fan recirc blend motor but I think that can wait.
I think the aircon clutch circuit just won't show healthy if one off the components in the loop are out, one of them being that duel pressure switch which is only healthy when between certain pressures, so it needs to have gas. Might be wrong mind, don't like wires.
I still have to do the fan recirc blend motor but I think that can wait.
I think the aircon clutch circuit just won't show healthy if one off the components in the loop are out, one of them being that duel pressure switch which is only healthy when between certain pressures, so it needs to have gas. Might be wrong mind, don't like wires.
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stopover
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As I started this I had better do an update. The aircon does not work. TestBook gave an Evaporator Sensor Fault and Heater Sensor Fault. TestBook could clear the Heater Temp Fault. Fitted new Evaporator and Heater sensors and same result on TestBook (unable to clear Evaporator Fault) Prior to this we had the car de-gassed (it was full) we changed the Drier Unit and both switches. Had the car re-gassed.
TestBook can Force the Compressor On result cold in the cabin (clutch OK). But no indication of a Grant A/C On so next is fish out the HeVAC and get the AVO on it? Incidentally The air/con will very, very occasionally work but only on a very hot day (havent seen any lately) and not very well and not for very long. Book symbol comes on after five Min's or so
TestBook can Force the Compressor On result cold in the cabin (clutch OK). But no indication of a Grant A/C On so next is fish out the HeVAC and get the AVO on it? Incidentally The air/con will very, very occasionally work but only on a very hot day (havent seen any lately) and not very well and not for very long. Book symbol comes on after five Min's or so
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Sounds like you still have an evapourator temp sensor fault, how much are they? easier to change than taking the hevac unit out. Can you test the sensor with a multimeter from known resistances for temps? Just hazarding a guess at what I would do.
Also does testbook have live data? perhaps you could take te sensor out and test still connected?
Also does testbook have live data? perhaps you could take te sensor out and test still connected?
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stopover
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Tested the one I took out and its spot on, didn't need changing? I also put a 1.8ohm resister accross the wires - no joy???
Beat me then I am afraid, You sure its not low on gas so the duel pressure switch isnt healthy. When you get a hot day the vapour pressure of the gas increases and could make it healthy. You would show up a clutch circuit fault then though I presume?
Sounds like you know more than me anyway. AVO what is that?
Sounds like you know more than me anyway. AVO what is that?
stopover
Active Member
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Well got the old HeVac out and poped in another I thought was a good one (same numbers 1998, mine is a 2000 car?) Air/con works! BUT the book symbol came straight on with left hand blend door fault that will not be cleared on TestBook Arhhhhhh. Put old HeVac on and blend motor works fine and travels correctly through Cold/Warm/Hot but no Air/Con and old message Evap sensor again. Put back replacement HeVAC and same Fault on Blend Motor at 119%.. I have been through the procedures for new ECU and reset and tried forcing it to no avail. Bugger.
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