23-06-2013, 08:49 AM
Right the aircon is controlled by the AC unit you use on the dash and partly by the engine ecu. The AC unit sends a signal to the Bitron unit (engine fan controller under the passenger side headlight) to switch on a fan to constant low speed.
When the AC is on, it only switches one fan on low speed. What most people who go slimline do is butcher the original fan cowling, keep all the wiring, mount the relay box somewhere and just wire the slimline to the primary fan (not the AC one). That way, it will come on low speed at 97 and high at 107 (think they are the gti temps) and will default to high speed if the brown sensor on the thermostat housing goes O/C so you can still put a switch in line and have your in cabin fan over ride switch.
When the AC is on, it only switches one fan on low speed. What most people who go slimline do is butcher the original fan cowling, keep all the wiring, mount the relay box somewhere and just wire the slimline to the primary fan (not the AC one). That way, it will come on low speed at 97 and high at 107 (think they are the gti temps) and will default to high speed if the brown sensor on the thermostat housing goes O/C so you can still put a switch in line and have your in cabin fan over ride switch.
Team Eaton
1999 China Blue 306 GTi6 - Eaton Supercharged - 214.5bhp 181lbft
1999 China Blue 306 GTi6 - Eaton Supercharged - 214.5bhp 181lbft