Our kits do not control the blower as that is done by the factory controls already in the car. The only connection is to 'detect' blower on which is the orange wire.
Bottom of page:
https://classic-retrofit.com/forum/index.php?/topic/1235-07-cabin-controls/#comment-1864
"For those using our half kit, you do not have to install our cabin button. You can use the factory blower switch to turn on the AC. This requires wiring the orange wire in our loom to the red/white wire on the factory blower 4 pin connector.
Installation of the half kit requires changing settings in the ECU. "
The ECU settings that need changing relate to the orange sense wire ( which detects the blower fan being on ). This is documented here:
https://classic-retrofit.com/forum/index.php?/topic/2472-blower-sense-voltage-what-does-the-orange-wire-do/#comment-4057
See main text for ECU settings and note the 'Automatic Compressor On with Blower" mode