have 85 IROC w/TPI 305 got it not running 1 1/2 yrs ago after it sat for a long time. but after some months of work it is drivable. all A/c components are present just needed to have system charged so I figured everything else is done why not. In addition I saw the fan was wired to run all the time so I left it as it was car runs at 210ish here in Texas which I figure is good enough for now. also the heater/AC blower motor only works on high, which i figure thats about where it would be anyway if it were operational. but after messin with it a bit the belt squeals, then it seems that the compressor isn't disengaging, even when blower is off so tinkered around a bit more and it is cycling so not a problem, but however today got tired of sqeaky belt so unpluged the compressor clutch and it idles at a rock solid 1700rpm which before it was fine at 650 rpm. so my question is does the ECM get a signal from the low side switch to tell it to goto high idle, even better is the ECM even involved at all with the A/C system the haynes manual schematics aren't very thorough. It really makes me sad how others can do hack job wiring on their cars but it is fun to try and figure out their madness.

 

No wiring diagrams listed for 85 TPI but both 85 carb and 86 TPI show links back to the ECM from A/c system.

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http://www.austinthirdgen.org/mkport..._continued.gif

 

Thanks for the schematics there great, I've been working on this issue over the weekend and I'm thinking it is an intermittant ECM failure, new one on the way will keep you posted