My 07 Defender is back at the dealers for a second attempt at fixing the A/C. The problem is to do with the thermo-switch which fails to cut out when cooling down. The core drops right down to freezing and consequently the heat exchanger ices up and very little air flows through (at least that's how I understand it). I noticed this about a month after I took delivery and the dealer fixed it. Things seemed to work fine for a couple of months then, after a few warm days I noticed it doing the same thing again.

It has been back at the shop since last Tuesday. The dealer informed me that they had a second vehicle doing the same thing AGAIN so they sent a technical query off to Land Rover Australia. They subsequently escalated the issue to Land Rover UK. The response came back to replace the exact same bit (thermo-switch) that was replaced last time.

Now I don't hold out much hope for this fix actually working and with the weather cooling down here it will most likely be October before I really know whether or not it's fixed. Logic would dictate that if you fixed something one way (on more than one vehicle) and it stops working again on both, then maybe there is something else awry.

Is there anyone else here who has had the same issue with their new Defender's A/C? I know most of you guys have just been through winter and don't get many 40degree days, but I thought I'd ask the question. I guess I'm just fishing to see if this is a known design fault, or I and the other guy just got our dodgy switches replaced with ANOTHER bad batch of switches.
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2007 Defender 110
1970 Alfa Romeo 1750GTV

The A/C is supposedly all fixed and seems to be working. I'll wait and see if the problem re-occurs after a month or so.
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2007 Defender 110
1970 Alfa Romeo 1750GTV

solmanic wrote:

The A/C is supposedly all fixed and seems to be working. I'll wait and see if the problem re-occurs after a month or so.

solmanic wrote:

Is there anyone else here who has had the same issue with their new Defender's A/C? I know most of you guys have just been through winter and don't get many 40degree days, but I thought I'd ask the question. I guess I'm just fishing to see if this is a known design fault, or I and the other guy just got our dodgy switches replaced with ANOTHER bad batch of switches.

one_iota wrote:

Was the switch replaced again or was it something else?

Hey, guys, just think of a domestic AC unit, and don’t get distracted by it being in a vehicle. A domestic unit will freeze up, and lose cooling efficiency, when it loses gas. This results in a lower pressure in the high pressure side, resulting in a lower boiling point of the refrigerant. At design pressure the boiling point is above 0 deg. C, hence plenty of condensation on the cooling coils, but no ice. As the gas leaks, slowly, the discharge pressure drops, and the boiling point of the refrigerant drops. We all know about trying to make a decent cup of tea, or boil eggs, at high altitude – the water boils at a much lower temperature, and you end up with maiden’s bath water or runny eggs. The same thing happens with the AC refrigerant, it boils at a much lower temperature. There was almost certainly nothing wrong with either switch, the problem was a slow – very slow – leak of gas.