Hello. ac pump on octavia with climatronic will not go. When it was supposed to be running I measured no more than 9v on the clutch. suspect that there should be 12v. has someone  seen something similar before and knows where the trouble is? 

Yes check all the wiring under the battery to the controller and any breaks in it

1 hour ago, Liverpool-Lad said:

Yes check all the wiring under the battery to the controller and any breaks in it

Seems like the wires dissapears into a bundle right by the ac pump. That bundle resurfaces just by the battery. There is a connector right by the battery (see the picture). That a part of the circuit? I presume the clutch gets its power from a relay somewhere. Do you know its whereabouts? Found some relays over by the firewall. Do you know if they are a part of this? (The other picture)

Its underneath the battery tray, a largeish control box.  On mine the positive had somehow degraded

Looks like this https://www.amazon.co.uk/Radiator-Cooling-Control-Replacement-Volkswagen/dp/B007TYMD8C#customerReviews

1 minute ago, Liverpool-Lad said:

Its underneath the battery tray, a largeish control box.  On mine the positive had somehow degraded

Thanks. I'll rip out the battery for clearance tomorrow and check it out.

Good luck, its bolted to the battery tray, you can see the 2 bolts connecting it up. 

 

My compressor eventually went a year or so after this fix, would not engage properly, so had a new one fitted and receiver dryer.