P38 aircon problem...

Hi all.
Have the following problem with my 1995 4,6HSE. The aircon have nott been regassed since I have had the car, for two and half years. It was kind of coolish, but not good. Today I have went along to have the system regassed. They have done it and informed me, that it is all okay, BUT the compressor does not get power from the...Where it is coming from?
They have tried to put direct power and the compressor works, but put the plug in and no joy.
Does anybody have any suggestion about where to look?
Thanks.

Under bonnet fuse box, check for sign or smells of burning. I suppose you have the aircon switched on? i.e. with the light out?

Yes, they have checked the fuse, so I was told. But tomorrow will check myself....
Thanks.
If anymore ideas let me know please.

Andras said:

Yes, they have checked the fuse, so I was told. But tomorrow will check myself....
Thanks.
If anymore ideas let me know please.

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Check the aircon gas pressure switch. It's the switch that completes the compressor circuit. Compressor will not run until this makes. If it has failed the system thinks there is no gas. The compressor will not run with no gas.

Thanks for that. Where do I find this switch?

Andras said:

Thanks for that. Where do I find this switch?

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The dual pressure switch that controls the compressor clutch is on the drier. You will have to degas the system to change it.

But if the system works with direct power to the compressor? Would that outrule the switch mentioned by you?

Andras said:

But if the system works with direct power to the compressor? Would that outrule the switch mentioned by you?

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No. But also check the wiring loom from the switch, it broke on mine.

Seen some more info on the rangerovernet, very interesting. Sounds like it indeed could be the switch mentioned above. To drain the system will be same price as the refill?
The switch is not too expensive..

Andras said:

Seen some more info on the rangerovernet, very interesting. Sounds like it indeed could be the switch mentioned above. To drain the system will be same price as the refill?
The switch is not too expensive..

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Why you no risen glashopper? If your compressor clutch engages with direct power then it is sound. The connection between power supply and compressor is dual pressure switch. It has several functions. It prevents compressor from running if there is no gas pressure, switches it on as needed when there is. It also switches compressor off if gas pressure gets to high and controls fan speed to cool gas in condensor.

Trimary switch, Wambo?

The Mad Hat Man said:

Trimary switch, Wambo?

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It's whatever you want it to be. But that's what it does, if it ain't working or there is no power to it compressor won't run that's for sure.

P38 Range Rover Aircon Tri Pressure Switch BTR9222 on eBay (end time 27-May-11 12:34:23 BST)


Is this is the one? Thanks for the help...

Andras said:

P38 Range Rover Aircon Tri Pressure Switch BTR9222 on eBay (end time 27-May-11 12:34:23 BST)


Is this is the one? Thanks for the help...

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Have you checked there is power going to it? Because you won't get anything out if there is none going in. That is first job to do before changing it. Would hate you to go get a switch degas fit it and find it was a loose wire.

Not yet, but I will do before buying a new one...I would hate that situtation too...

Andras said:

Not yet, but I will do before buying a new one...I would hate that situtation too...

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Good test it out first. Also the switch is the right one. But the term tri pressure switch is decieving. It is in fact a dual pressure switch. With two seperate sets of contacts. One side is used to put power to the compressor clutch, it has three positions. OFF when no gas pressure. ON with gas pressure. OFF if pressure gets too high. Other side controls fan speed and has two positions OPEN fans run in series (slow). CLOSED fans run in parallel (fast). Fans themselves are switched by single pressure switch, two positions OPEN fans stopped. CLOSED fans powered. On the petrol engine condensor fans come on whether air con is on or not to assist engine cooling. On the diesel they don't.

hi all

Ive had all sorts of problems with my range rover heating ive changed the blend motors with new ones but the air con not working ive changed the compressor but the clutch dont seem to be engaging could this be coz i havent got it gassed yet ???? if so ill get it gassed and try again if it still dont work any thing else i can try any help will be greatful

cheers tom