M20 AC compressor control and DME

[zaq123]

Motronic DME has 2 pins , #40 - pressure cut 0ff and For Sale & Wanted - AC in. Can anyone explain why dd they make these 2 DME connections? Idle up for when the compressor is on? If so, why both? From the diagram, it looks like DME sees 12 input after the pressure switch which (switch ON - increase idle; switch OFF - normal idle). Why is there a second input from the AC button?

[zaq123]

no one knows why stock DME needs to see both of those signals?

[ForcedFirebird]

It's a loop. If the DME sees AC on only from the dashboard, and the pressure cycles, then the idle would stay up during the cycle. So you need two variables, AC requested by dash, then the cycles of the compressor.