Outer Limits 4x4 Board

Hi all, My aircon on my Disco 3.9 V8 has an intermittant fault. Briefly it stops working for a little while, then comes back on. Some times I lose all power momnetarily to the fan also, which a sec or two will come back on.
1. There does not appear to be any 'Icing up of the condensor'.
I thought it might be the TX valve on the evaporator,. but, this is what I discovered so far.
A multi meter test on the connector to the compressor clutch shows .06 - .09 volts when it is not working. When it works there is 12-13.5 volts.
I direct fed battery power to the compressor clutch and it engages. Also I get good clod air in the cabin.
2.Question, if the TX valve was faulty, why would I get cold air? Wouldn't it block the circulation of the gas preventing cooling?
There are also an Evaporator Temperature switch to sense temp to exterior fins- to detect' icing' and a Dual pressure switch to monitor gas pressure on the High pressure line.
3. May be one of these is causing my problem, but how do I test them?
4. Then there are relays under the dash to control Compressor clutch.
Any advise would be appreciated. Especially if some one has had the same problem and fixed it.
Finally, it I was to by pass the dash on / off switch and temparily wire in a new on /off switch direct to the compressor clutch., could I damage the system with over pressure of it running constantly?
Sorry for the long post.

The TX valve in my Feroza was stuffed and I could get the aircon to run for about five mintues and then it would die. From memory it would sometimes come back on again by itself, but not for long. The valve was blocking up intermittently and causing a high pressure condition - thus the control module was shutting off the compressor.

Just some useless info that may be of use- took me about a year to finally work out what was wrong!

This place could be of use to you too www.jayair.com.au ; they have an online catalogue with pics and part numbers of different aircon bits to suit most Aussie vehicles.

Thanks Murcod, If it is in fact the TX then it's the marathon Dash out episode.

Mine wasn't that bad to do- I ripped the glovebox out and was able to pull everything out from underneath the dash.

If you end up replacing it and have got the old R12 gas, then it would be the perfect time to change the TX valve to an R134A type. Suposedly they are a bit different.

I checked the A/c workings on the LR Rave CD and it listed the circuitry for the A/C.
I replaced the A/C logic and the Clutch relays, and it now works.

When I disconnected the Logic Relay whilst there was battery power to it I coud see sparking internally from the inside relay contacts through the yellow plastic casing.
I Think It was loosing connection intermitantly and causing the A/c to switch on and off.

I replaced them with 2 servicable relays and it works perfect now.
Drove around all day todday and the A/c was operating normally.
Thanks for all your advise guys.