Hondata

My mechanic told me he connected the air con wirings directly to the S300.

When i switched on the air con, air con compressor/clutch starts.

When i switched it off, air con compressor/clutch still runs. I need to switch off engine completely to turn off the air con.

I do not like this. Pls help. Which wiring should I remove/deactivate from the S300?

Not knowing how this is wired in your car, it is nearly impossible to say what the problem is. I would highly suggest getting a Helms manual (factory service manual) for your vehicle to make sure everything is wired correctly.