JohnP38 · Mar 24, 2011

Hi All, my HEVAC has the book symbol come up fairly consistently recently.I have used my BBS MSV and have found the fault message "aircon compressor control cct short or open circuit".to be the cause.Yes I did clear the codes and It has come back consistently.
So my question is,is that the actual fault or is the compressor not being engaged because of low gas or a fault in one the interlocks that allow the compressor to be engaged such as the trinary switch.
Opinions or experiences welcome

wammers · Mar 24, 2011

JohnP38 said:
Hi All, my HEVAC has the book symbol come up fairly consistently recently.I have used my BBS MSV and have found the fault message "aircon compressor control cct short or open circuit".to be the cause.Yes I did clear the codes and It has come back consistently.
So my question is,is that the actual fault or is the compressor not being engaged because of low gas or a fault in one the interlocks that allow the compressor to be engaged such as the trinary switch.
Opinions or experiences welcome

Compressor open circuit means either switch is duff if you have gas in or there is not sufficient pressure to close the compressor circuit. Compressor will NOT run if there is no gas pressure.

Datatek · Mar 24, 2011

Low gas pressure is the most likely cause although the book symbol does not always appear with no gas.

Irishrover · Mar 24, 2011

It could also be a faulty thermal switch which is mounted on top of the compressor towards the rear (Has 2 wires on it). I have had mine linked out for years without any problems. Most compressors do not have these fitted. Yet another case of LR going overboard with the design !!!

If the gas overheats, the pressure in the system will increase and be picked up by one of the system pressure switches which in turn will shut the aircon down.

JohnP38 · Mar 24, 2011

I fiddled a bit more this PM and then took it to the local regas place.They connected up and said there was little or no gas and when they tried to evacuate the system the machine came up with "Leak detected".So thats were it stands,as they are not able to go further as they can only refill if no leaks are detected and they do not do diagnostics.
So now to find a place that does do aircon diagnostics and dosent charge a fortune!
Any recommendations?

wammers · Mar 24, 2011

JohnP38 said:
I fiddled a bit more this PM and then took it to the local regas place.They connected up and said there was little or no gas and when they tried to evacuate the system the machine came up with "Leak detected".So thats were it stands,as they are not able to go further as they can only refill if no leaks are detected and they do not do diagnostics.
So now to find a place that does do aircon diagnostics and dosent charge a fortune!
Any recommendations?

You'll have to get it leak tested should not cost a lot. Seems a bit strange a regas outfit does not do leak detection. Or are they just a cowboy outfit.

Irishrover · Mar 24, 2011

Find a place that will fill it with Nitrogen & leak detector. My thoughts are...top l.h. corner of Condensor. If it's a bad leak you will hear it.

JohnP38 · Mar 24, 2011

wammers said:
You'll have to get it leak tested should not cost a lot. Seems a bit strange a regas outfit does not do leak detection. Or are they just a cowboy outfit.

Their speciality is tyres .I had tyres fitted to my ford there a while ago and remembered seeing a sign about aircon regasing.So not an aircon specialist.
Just phoned an aircon speciailist and was quoted £59 + vat for a pressure test and diagnostic of the leak.I guess the solution could be a tad expensive if the compressor or evaporator has a leak!

Irishrover · Mar 24, 2011

Doubt it's the compressor or evaporator. P38 condensers are notorious and usually the prime suspect. If it's a hose, look up "Pirtek" in the Yellow Pages, they can swage a new hose for aircon systems on to your existing end fittings. Don't go for a normal hydraulic type hose as the refrigerant will attack the hose and cause more problems.
With regard to Pirtek, if you take the hose to their office/works, they will do it while you wait and their prices are very reasonable.

Datatek · Mar 24, 2011

Most likely condensor in front of RAD. Easy DIY job to change.

Irishrover · Mar 24, 2011

Datatek said:
Most likely condensor in front of RAD. Easy DIY job to change.

:amen::5biagree:

JohnP38 · Mar 24, 2011

Thanks gents,I will have it pressure tested next week and hold thumbs it is a pipe or the condenser.havent had it checked for the six years I have owned.It operated for three years in the heat in South Africa and three years in the cold of the UK,so I guess its done a good job.

Irishrover · Mar 24, 2011

Don't want to shock you but I had a genuine Condenser that lasted less than 2 years...so much for genuine parts !!!
The replacement was purchased off Ebay for less than half the price and has been fine for over 4 years now. I have the aircon checked every year and the system is still as full as it was when the condenser was fitted.

The Mad Hat Man · Mar 24, 2011

JohnP38 said:
havent had it checked for the six years I have owned.

Irishrover said:
I have the aircon checked every year.

Dont that tell yu summat?

JohnP38 · Mar 24, 2011

The Mad Hat Man said:
Dont that tell yu summat?

prehaps,but checking the system usually means only a top up,a complete evacuation and refill is generally quite expensive.If a leak is found you still have the repair costs.The system will leak out by about 10 to 15% annually no matter how leak tight it is.
Irish has had the misfortune of replacing his condenser twice.i dont see how annual checking would have prevented that though.

bison4x4 · Mar 24, 2011

I have had to do the air con condenser on three of the P38's I have bought.
They have all failed in the top left corner, as mentioned above.

I get them from here and have had no issues:

Range Rover P38 Air Con Condenser with seals oil & dye on eBay (end time 28-Mar-11 15:29:10 BST)

They come supplied With New 'O' Rings (Seals), 65ml of Pag Oil and Leak detection Dye
You must change the 'o' rings when doing the job, and coat them in the AC oil, to prevent sealing issues - and this company saves having to buy them seperatley.
You don't have to remove the front bumper either, although it tells you to in RAVE.

I can do the job in around 2 hrs now!

JohnP38 · Mar 24, 2011

bison4x4 said:
I have had to do the air con condenser on three of the P38's I have bought.
They have all failed in the top left corner, as mentioned above.

I get them from here and have had no issues:

Range Rover P38 Air Con Condenser with seals oil & dye on eBay (end time 28-Mar-11 15:29:10 BST)

They come supplied With New 'O' Rings (Seals), 65ml of Pag Oil and Leak detection Dye
You must change the 'o' rings when doing the job, and coat them in the AC oil, to prevent sealing issues - and this company saves having to buy them seperatley.
You don't have to remove the front bumper either, although it tells you to in RAVE.

I can do the job in around 2 hrs now!

Thanks useful info.How did you determine where the leak was?

bison4x4 · Mar 24, 2011

I buy the self recharge R134a in a can, about £10, carefully put some in the system following instructions. Shut off the engine and listen for leak.

The cans are about a tenner but I had to buy a valved hose and pressure guage the first time.

If you want I can try and find the info tomorrow, but off to bed now.

Mike .

JohnP38 · Mar 24, 2011

bison4x4 said:
I buy the self recharge R134a in a can, about £10, carefully put some in the system following instructions. Shut off the engine and listen for leak.

The cans are about a tenner but I had to buy a valved hose and pressure guage the first time.

If you want I can try and find the info tomorrow, but off to bed now.

Mike .

Thanks Mike,appreciate the info tomorrow.
Cheers
John

JohnP38 · Mar 25, 2011

bison4x4 said:
I buy the self recharge R134a in a can, about £10, carefully put some in the system following instructions. Shut off the engine and listen for leak.

The cans are about a tenner but I had to buy a valved hose and pressure guage the first time.

If you want I can try and find the info tomorrow, but off to bed now.

Mike .

Found Autokool online this am and have ordered cans from them.Hopefully will help to sort this out.Must admit I wasnt aware you could get DIY aircon regas kits

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