Hi all, new member here. I have a 2008 LR3 4.4. AC has been working really well but went out yesterday after a long trip. A few notes:

1. For the last few days I've head a rapid clicking coming from the passenger side of of the vehicle with the AC is on. This didn't sound like a clutch engagement...too rapid and softer sounding.
2. Yesterday we took a long (4 hour trip) with the AC on and working well the entire way.
3. After we returned home I had to run an errand and had no AC (no clicking either)

Tried adding 134a using a gauged canister I already had. System is not pulling any freon into the low side.

I threw my AC gauges on it and get 105 low side and 125 high side at idle and I'm not sure the compressor is engaging.

Wondering if the group knows how to force the compressor to engage.

Also open to other ideas, fuse, relay, etc. New to LR AC so learning here as I go.

Thanks in advance for any advice. Of course it's been 90 in Seattle lately so AC that is rarely needed around here is pretty nice on days like this.

 

You are correct when you say that the clicking sound on the right hand side does not sound like the clutch. This is primarily because the AC compressor in the 3 is always on and does not have a clutch as AC compressors used to have.

R134a flow is controlled via a variable orifice located near the "heater". As such, in the traditional LR manner, it is near impossible to get at.

The link below is to a number of files I have collected related to the HVAC systems. One of the files is a 12 pdf that explains fairly well how the system operates.

In terms of fixes, the simplest is to find an AC shop that is not afraid of "that exotic foreign stuff" and just get the system charged. You might also ask them to inject some UV dye into the charge. A recharge may not solve the problem but it will give you a starting point.

Also do a HVAC reset per the instructions below. It costs nothing and who knows... I usually do it at least twice in a session and rarely get any flashing LEDs but I think something good occurs anyway. No bad is ever done.

Heating AC System Test

The issue with the A/C may be a Control lever/Recirculation flap or some other control door bit.

With the ignition off, press and hold the ECON & RECIRC buttons while turning the ignition on. There is no need to start your 3, but I do as a matter of routine as it ensures sufficient voltage to run the system computers.

The control module will then compare the current HVAC actuator motor positions with the values stored in the module and will indicate an error by flashing the ECON LED.

If there are no errors, the LED will go out and the system will function normally.

To confirm that there are no errors, turn the ignition switch to the OFF position, then back to the ON position.

Observe the operation of the programmed defrost LED.

If there are errors present, the programmed defrost LED will flash and the system will attempt to calibrate itself.

Below is the link to my HVAC files.

DISCO3.CO.UK Photo Gallery - Heater Air Conditioner System

 

Thank you for the detailed response. I'm reading the documentation now. I did know that the compressors are variable stage (no clutch) which got me thinking the issue might be with a relay or the pressure sensor. Right side, engine bay suggests relay to me.

The thing is I've read posts on this forum (and another) that the R19 is the AC relay...but in my LR3 there is nothing in that position.

Also, pressure at idle show freon in the system. I'm seeing 125 high side and 105 low, which suggests the compressor isn't fully engaged. I also attempted to charge the system but the system would not pull freon (using premixed with oil and leak dye).

Things I'm thinking about:

Relay
Pressure Switch
Compressor

 

Also - is there any way to bypass everything and engage the compressor? If I can engage it and I see a proper high/low pressure differential (and add freon is needed) that gives me a test that might eliminate the compressor from the list of possible failures.

 

I assume you have been studying the 7 page wiring pdf per below and also located on that link above.

You will note a 40.0 amp fusible link 12E related to the front fan blower relay that they call R176 on the pdf. I think this is R16E in the engine compartment fuse and relay panel located beside the battery.

Also do you have the optional rear air conditioning and fan?

If so, then you will also have a relay called up as R214 in the pdf and shown on page 5/56 of the attached pdf. This is rear fan relay called R10E, also in the engine battery fuse box area.

Relay R16E and R10E should be identical relays. If they appear to be so, then swap the two. I would think that if you have heat or at least ventilation, that the R16E relay is OK but that is a cheap way to check.

Basically the fan relays control the fans based on instructions from the Automatic Temperature Control Module, (D243); also the AC solenoid valve controls the flow of R134a, again based on instructions from the ATCM.

There might be a way to "load" the compressor but I expect it is via the T4 computer setup as the compressor and R134a flow is controlled by the Automatic Temperature Control Module computer, (D243), located between/under/behind the two temperature set rotary *****.

No AC clutch means there is nothing to engage and in reality the compressor is always engaged - just not circulating much R134a. I think it is the Refrigerant Solenoid Valve (D332), page 4/55 that regulates the flow of R134a depending upon what instruction is received from the Auto Temp Module, (D243).

http://www.disco3.co.uk/gallery/albu...cal_wiring.pdf

 

What was the issue with the AC? I just experienced the same issue.

 

I'm pretty certain it's the compressor. Trying one last thing prior to a replacement.

Fortunately we live in the Pacific Northwest so it's not terrible that the AC is out.

 

Replaced a compressor and drier/accumulators this weekend with a new Denso from Amazon (thanks pgoodrich). The old one was clearly the issue. It had a catastrophic failure as I found bits from the pulley on the skid plate once I started the project.

Gotta say - this was a pretty tough job. All in all about 10 hours of work which included the compressor replacement, removal of the high pressure side of the power steering pump (necessary to remove the forward, lower compressor bolt) and the front bumper, bumper, etc in order to access and replace the drier.

Charged the system and everything is working perfectly. Good thing too as we're having record temps here in Seattle.

Happy fourth everyone.

 

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