Wanted HVAC direct control bounty

Edit: I am offering 250E bounty for managing HVAC fan through canbus. Any other medthods can be rewarded if they are technically reasonable and do not heavily interfere with the vehicle electronics. For example, when turning off engine, the HVAC fan is still running idle for a while, and a relay in the engine bay fusebox clicks when done. That fusebox is hard to reach (it is under the coolant reservoir on the passanger side on the LHD model) - there might be a solution to energise that relay.

I am offering 500E bounty for information regarding controlling the HVAC fan directly through the dash wiring loom. Webasto does this on the dedicated solution for the Ineos Grenadier, with a special wiring loom, see pictures. If you have one and willing to share the wiring and logic, I would be very grateful and glad to offer the reward.
More details here: https://www.webasto.com/en-int/newsroom/press-releases/parking-heater-ineos-grenadier.html