Whew! That was easy!
Yes, as pointed out, defroster mode or any A/C mode turns on the solenoid. Of course, if they're not adjusted properly, you may never see it. It appears the solenoid itself needs adjusting. I think it's a 7/16" bolt head on top of the plunger you can simply screw in and out to set your "A/C" idle. From my 87 and 85 which are both originals, the idle is BARELY ticked up with the load on the compressor. It's supposed to be nearly seamless, but we all know that isn't always the case.
Simply turn in the screw some and I'll bet that solves the problem.
Yes, as pointed out, defroster mode or any A/C mode turns on the solenoid. Of course, if they're not adjusted properly, you may never see it. It appears the solenoid itself needs adjusting. I think it's a 7/16" bolt head on top of the plunger you can simply screw in and out to set your "A/C" idle. From my 87 and 85 which are both originals, the idle is BARELY ticked up with the load on the compressor. It's supposed to be nearly seamless, but we all know that isn't always the case.
Simply turn in the screw some and I'll bet that solves the problem.
