I would try recharging it first. Go to your local autoparts store and buy a A/C recharge kit, its about $20. Follow the directions and see if that does the trick. You can be low on R-134 and the compressor will still cycle but the refridgerant level will be to low to do anything.
Its a cheap and easy place to start. And you can do it yourself in yoiur driveway.

 

A blocked duct would not cause you to get warm air. If all is working, go get the refrigerant changed and at least that part will be covered. But I'm pretty sure your problem will be fixed right there and then.

 

thanks guys.... i will try on the weekend and post the result here

 

Strangely - My A/C in my 98 Disc (78K miles) also went out. The fan blows hard - just warm as hell. How does one test the compressor? Looks like the belt is spinning. A/C light turns on. No cold air, happened all the sudden. Air did not get less cold, just suddenly not cold at all.

Thanks Guys!

 

To test the compressor, start the engine, open the hood, and with the A/C on watch the A/C compressor, the clutch should kick on and off.

 

Thanks. As it turns out - simple fix - blown 30 Amp fuse for the compressor.

yuenie - check yours before you tear into dash......

 

Thanks pedro_malo, I am not as lucky as you because my compressor is working.

 

This could be completley useless but, Ive heard that the range rover classics do this when the temperature sensors for the a/c are bad or need to be cleaned... its probably useless info but it might be worth a shot. You may also want to try feeling the compressor lines to see if its cold or not, or you may not be able to cause I don't know to much about the Disco II. (be careful some of those lines get really hot and cold).