AC Idle Up Circuit On MS2e Using MS3x Table Switch Input Circuit
 

Hi All,

Looking to implement this circuit on the proto area of my MS2e for the Air Conditioning switch input to use the AC idle up code. Brain suggested this in another thread and I just wanted to make sure I was hooking it up correctly w/ both 12v and 5v being involved with a CPU pin. I've got the components in the diagram on the way. I think my main hangup is just knowing what VCC is for a voltage. I'm pretty sure 5v is the answer but just want to be sure. Otherwise, it looks like the input I'm looking for on my 94 is 1Q. Thanks ahead of time.
Attachment 177063

diagram markups look good, use s12, not s12c. vvc is 5v.

what input would you use?
what output would you use?

you could build a simpler circuit, but that one will suffice:

http://www.msextra.com/doc/ms1extra/...s/lowinput.jpg

doesn't the MS Labs MS2 Enhanced already have a/c idle up?

I need to sleep more. It's a DIY MS2 not an ms labs ms2e. Thanks much Brain.

Not exactly sure what the guy in the thread I found had going on, but he said he built that circuit you suggested and it only worked on blower setting 4.

You were thinking it was because the voltage didn't drop far enough and suggested building the ms3x table switch in circuit

oh okay. I actually had that issue once, but my car had some weird ass voltage offset problem, using that circuit did help a little, but there was other things going on in my setup.

like i said, either input circuit will work.

I tried implementing this circuit but couldn't get it to work. The output was stuck at 5 volts wether or not a/c was on or off, at any blower speed. 2000 Miata, using pin 1P as the A/C input pin.
Measuring the wire directly shows 12v with A/C off, then it goes to 2.5v when A/C is on.

I ended up using an OP Amp instead of messing with complicated circuitry.