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Trud
Joined: 26 Aug 2016 Posts: 2 Location: Somerset
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Posted: Sat Jul 08, 2017 4:59 pm Post subject: Air con |
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Hi
Does anyone happen to know how the air con is controlled so it works? The system is fully gased but the compressor and the condensor fan do nothing. There is a relay clicking under the control panel when the a/c knob is turned, the interior a/c fan runs normally and there are no engine ECU faults. Also both a/c fuses are good. (Hubby is an automotive a/c engineer but can't find out how the control systems work, or obtain a wiring diagram)
Thank you
Trud |
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Romadog2004
Joined: 06 Aug 2008 Posts: 625 Location: Radnorshire
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Posted: Sat Jul 08, 2017 5:33 pm Post subject: |
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Have a look at this link
[url]ww.legionlandrover.com/manuales/electrical%20schemes%20-%20defender%20v8.pdf[/url] |
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Jimbo
Joined: 13 Dec 2013 Posts: 9 Location: Kent
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Posted: Mon Jul 10, 2017 6:36 pm Post subject: |
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Does the clutch on the compressor engage when the relay clicks?
I've just fixed my air con and it turned out to be the thermostat that is located next to the 3 position fan switch. I shorted out the contacts and it all sprang to life.
Many "professionals" had checked over the air con system but none of them spotted this. _________________ 50th GB070 |
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50Def
Joined: 15 Jan 2016 Posts: 25
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Posted: Mon Aug 07, 2017 6:22 pm Post subject: |
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There is a thermostat control on the RHS of the fan speed switch. Turn it fully clockwise for full cold. The thermostat sends a signal to the ECU that then (if the engine is not overheating) sends power to the compressor clutch.
As already said you can connect the two wires that go to the thermostat to see what the system does. It should get the compressor going. This is only a temporary fix as the system will then be on permanently and will freeze.
There is also a switch on top of the received dryer that senses for low, medium and high pressures and will prevent the system from operating if the pressures are low or high.
The LR thermostat (in my opinion) is pretty rubbish as it allows too big a temperature range - the vent temperature on full cold can oscillate between 0 degrees and up to 8 degrees that is more than noticeable and makes you think the system is not working. For hot climates I have replaced it with a on/off sensor (de-ice switch) from a Discovery 300tdi with a much smaller temperature variation and the vent temp is constantly cool (but can't be varied)
Hope this helps. |
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Adbseries3
Joined: 29 Jul 2015 Posts: 55 Location: East sussex
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Posted: Wed Aug 09, 2017 8:33 pm Post subject: |
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Just following on from this, my own AC blows reasonably cool when the engine is first turned on, but by about 30 mins in, once the engine is hot, it blows slightly warm air, so time to turn off and open a window! Is this the norm? |
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MikeB
Joined: 20 Dec 2007 Posts: 131 Location: North Warwickshire
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Posted: Sat Aug 12, 2017 9:46 pm Post subject: |
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The fan in front of the radiator is controlled by the ECU and will not always be on when you have the aircon on. My compressor clutch sticks sometimes and requires a tap with a hammer to get it to engage. A spray with WD40 into it helps for a while. |
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