Hi Folks, So I put an ABF (97' GTI with Climatronic) in my 91 Mk2. I removed all the unnecessary wires from the mk3 engine bay loom along with the fan control relay box. I am running a stock Mk2 fan. Along with the engine conversion, I am installing an AC system that came from a 91 Mk2 GTI 16v. I am using the mk3 AC compressor, everything else (pipes, switches, relays, wiring) is mk2 parts. So, when cleaning up the ABF wiring loom, I left one wire dangling ECU Pin 39. I forgot where it was connected to originally in the mk3 application (it was a long time ago). Is that a signal wire for the ECU when the AC compressor and fan engages, so that the ECU can compensate the load with altering the idle speed? If it is so, where should I tap it in to?
funnily enough I posted about the same thing yesterday! Have a look at the wiring diagram in here, ECU pin 39 on the ABF ECU is 'all switches OK and AC active' trigger, so is placed after all the switches on the wire into the FCM: https://clubgti.com/forums/index.php?threads/abf-wiring-diagrams.287507/
So when the low pressure switch turns on the AC compressor, or high pressure switch turns off the compressor and fan, it signals the ECU with +12v. Since I'm not returning to the mk3 fan control unit, the question is what is the equivalent in a mk2 setup. I have the CE2 plug N in the fusebox. It seems that the N/05 AC Switch is not the one. N/04 A/C compressor (via thermostat and pressure switches) A/C Relay Compressor Output Green/Yellow I think this would be the mk2 equivalent? If that's the one, I could just tap that ecu pin 39 wire to this terminal in fusebox? Sorry, I'm a bit of a dum dum when it comes to all things electrical. And the system is not yet filled up, so I can't really test it now. I wanted to sort out all the wiring before filling it up. Thanks Rubjonny!
sorry I miss-read! Thought you said you were using the MK3 wiring. For MK2 wiring you would put it on the green wire spade hanging about near the fusebox, its on the N/4 wire AC relay trigger for the compressor, bottom right: