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UtilityTruck



Member Since: 09 Jan 2014
Location: Oxford
Posts: 463

United Kingdom 
AC Aircon trouble shooting. When should cooling fan start?
2.2 2014 110”

Some time back the A/C effectiveness seemed to drop off- it still works and blows cold air, but it struggles to keep up when it’s really hot and it used to be a lot better.

Prompted by this thread; https://www.defender2.net/forum/topic72615.html

I realised I could not remember the last time my cooling fan for the AC had kicked in.

Following the diagram in this thread; https://www.defender2.net/forum/post385404.html

I’ve checked fuse F6(20A) and F14(5A) in the battery junction box that are related to the AC (I think F6 is for the fan). Both OK. Fuses in the dash fuse board are also OK.

When AC is turned on, Relay R181 for the compressor clutch clicks and I can feel the pipe on the compressor getting cold. Relay R117 for the fan never clicks and the pins on the fan connector at the condenser always read 0V. So I swapped the relay out for a known good one, no change.

So my question is, when should the fan for AC be on??? Some have said in the other thread it comes on with AC, some that the ambient temp has to be higher.. does anyone know the actual logic employed? It’s about 22degs here today. [/i] 2014 Keswick Utility 2.2
Post #834041 29th May 2020 1:42pm
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LandRoverAnorak



Member Since: 17 Jul 2011
Location: Surrey
Posts: 11240

United Kingdom 2013 Defender 110 Puma 2.2 USW Orkney Grey
The detailed answer is within Widgets' post in the first thread that you've listed, which can basically be summarised as 'it depends...'. It's also worth noting that it may not actually be obvious when the A/C fan is running as the fan noise that people reported was almost certainly the viscous engine cooling fan.

Your not-cold A/C is most likely a sign that it needs to be re-gassed. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia
Post #834048 29th May 2020 2:15pm
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Martin
Site Admin


Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6459

United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
The condenser fan relay is controlled by the ECU and isn't simply on when the AC button is pressed.

To be honest, it hardly runs in my experience, perhaps at high engine temperatures/load.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #834051 29th May 2020 2:22pm
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UtilityTruck



Member Since: 09 Jan 2014
Location: Oxford
Posts: 463

United Kingdom 
Thanks, I’ll look at a re-gas! 2014 Keswick Utility 2.2
Post #834053 29th May 2020 2:32pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 19449

United Kingdom 
I think LRA has the answer, over time the Air Con effectiveness depletes so needs to be re-gassed.
On the bright side it’s not very costly. Smile Diesels Lives Matter. ⛽️🛢️👨‍🔧🧰⚙️
And if You Love the Country, then we’re on the same side ~
I got’ love for Britain, I got’ British pride’. 🇬🇧
Post #834060 29th May 2020 3:08pm
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Bluest



Member Since: 23 Apr 2016
Location: Lancashire
Posts: 3993

United Kingdom 2007 Defender 110 Puma 2.4 XS CSW Java Black
I recall someone telling me it doesn't run is there is insufficient gas pressure in the system as well. So lack of fan could a sign of needing a recharge.

Contrary to others, my fan does run a lot, even in relatively cool (not cold) conditions. It's quite easy to hear it kicking in and out from outside the vehicle and is distinct from the engine cooling fan noise. 2007 110 TDCi Station Wagon XS
Post #834067 29th May 2020 3:41pm
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Martin
Site Admin


Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6459

United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
The compressor won’t kick in if there’s not enough gas pressure.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #834157 29th May 2020 9:32pm
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bluebottle



Member Since: 08 May 2015
Location: Not in my Landy enough!
Posts: 705

United Kingdom 
It also shuts off if someone has overfilled the system... ask how I know Rolling Eyes
Post #834349 31st May 2020 7:21am
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