Air Con Compressor

2013 Jimny.
I had a completely flat battery and traced a current draw to the air con compressor. With everything turned off as soon as I reconnect the battery the compressor goes 'clonk' and draws about 2 amps. I've temporarily disconnected it.

Any ideas?

The A/C compressor is most likely a clutch style compressor, and the clutch is controlled by a relay, which is either shorted, or being commanded closed by the ECU.

Which relay? 2 are in with the fuses and 2 are attached to the side of the fuse box.
I will take a photo tomorrow.

You should be able to feel or here the relay engaging as you connect or disconnect the battery. Also it will become a tiny bit hotter than the other not engaged relays. and of course check the color of the wires to the Ac-solenoid/magnet and see if similar colors can be found at any relay.
Also if you disconnect the relay and the current stops drawing you found it as well..

If the relay is faulty it may not "click" if it's welded short circuit.
I've not checked as it's too cold for my old bones, but I assume the electric clutch on the compressor has a connector local to it?
If so you could unplug this to temporarily remove the clutch and see it this is the actual reason for the current. 
After this you may still need to find that relay, but at least your battery won't go flat whilst you check.

I could be wrong, just putting a suggestion forward which may help.
 

That's exactly what I did. It's stopped the battery drain so car is usable. Like you I thought I wouldn't hear relay clicking if at fault.
When weather warms up a bit I will try, by process of elimination, to identify which relay it is.
I was rather hoping someone would tell me - so I could go straight to it.

If no one comes forward with the answer I will try and hear which relay it is on ours. Off work tomorrow so as long as it's not raining I'll take a look.

I've failed you, sorry.
I did look, but it's impossible for me to hear the relay involved with the AC clutch as the clutch itself is very loud. I'll try and find any circuit diagrams I may have and hope they give a clue.

Thanks for checking.
I confess that now the car is working with the compressor disconnected the urgency to find the relay has gone. I will wait until its not so cold outside.
I did find this photo on the web. This is exactly the same fuse / relay box as mine.