Bypass aircon compressor inhibitor???

Hi again Volvo gurus!

I need to somehow bypass the switch(es) that stop the aircon compressor clicking in. What happened was I put some leak sealer in the system (to try and fix a condenser seal leak) but there isn't enough pressure to start/open the compressor.

I've tried shorting out the switch near the bulkhead, that didn't work. There's 3 connections on the low port but I don't know which ones to short (if any), I tried a combination of 2 and the engine cut out :-(

Any help much appreciated as I'm a bit stuck!!

Thanks

[Chris_Rogers]

Helps to say which model / year, but one way is to take a fused supply straight from batt + to the compressor clutch.

Sorry, it's a V70 10v 1998

Thanks for the idea, but where's the + termonal on the compressor clutch? Would it be on one of the 3 terminals on the low port connector? If it is, any idea which one?

Thanks

[Chris_Rogers]

I haven't got the wiring diag. for your car, and some info will depend on whether you have ECC or not.
On the 850 with ECC the pressostat switch has two wires coloured Grey & Blue/Grey this is the one in series with the clutch and the one you want. It's situated at the rear of the engine.
The three wire pressure sensor basically tells the engine ECU how hard the A/C is working to adjust idle speed etc.
That's all the info I have, so I hope it's of help.

Thanks for that, I'm assuming it's the switch near the bulkhead, centrally located, at least I'm hoping it's that one! I'll go with the colour coding.

Thanks again, mind you I think summer's over by the look of it!

Cheers

[pettaw]

Yes, Summer is over *sigh* but don't stop using your aircon at least once a week for ten minutes to run fluid through the system and prevent seals, hoses, compressors etc springing leaks.

[Mike Arnold]

I am not familiar with the ecc on the V70 family but I would bet it is similar to the other Volvos.

If you need to run the compressor then taking the electric clutch connector on the compressor to +12v will pull it in (if it does not you have a clutch failure). Beware, if you have low gas you will not have a method of keeping the compressor supplied with oil so it will seize after a while.

Some a/c systems have high pressure switches (to prevent it exploding) and low pressure switches (to prevent the compressor running without fluid) as well as temperature sensors to prevent running in winter or running when over-temperature. Another variant is Rover who use a combined hi/low pressure switch.

In modern systems all the sensors go into a microcomputer and you cannot work out what is happening.

This may not help much but might give you one step forward.