New relay for compressor clutch

[nishweth]

Hi i have bought a secondhand astra 1.6 saloon in which a seperate relay was being installed by previous owner. In that relay one thick wire is coming from relay to ignition wire. I think this relay is for compressor clutch. Also i have found two wires are coming from a ac cutoff thermostat switch which is fitted behind dashboard. I want to bring this back to genuine condition. Please advise. Where is the company ac relay located. On thr firewall relay box there is one purple relay,3 fuses and one green relay is missing.