wiley42

I'm putting the finishing touches on a build that has a OBDII EG33 swapped into a non-Subi chassis, and I'm at the "chasing up loose ends" stage of the project. As part of that, I'm trying to track down the voltage levels on pin 61 of connector B59 (the honking big connector for the ECU), which is fed from pin B17 on of the Auto A/C controller. While this signal shows up in the FSM prints, there's no actual description of the signal, but it appears to be the aux air control input from the environmental control system to the ECU, responsible for modifying the schedule for the idle air valve (some Subi four bangers have a similar signal). Just hanging out in the breeze, the line is effectively at zero volts; with a scope on it there's some noise that's picked up from the harness suggesting both that it's active low and not being actively pulled down by the ECU (the fact that grounding it takes out the noise but has no other effect on idle speed further supports this). This in turn implies that the Auto A/C module pulls it up when additional air is not required, but I don't know if it wants to be pulled to +5 or +12. Digging through the FSM and the forums hasn't turned up hints, and my DuckDuckGo foo has failed me. Does anyone know what the voltage levels are supposed to be, or, barring that, would someone be willing to see what's present on that line with the A/C off and again when on?