Toyota Repair: Corolla A/C, compressor clutch, 4afe

Question
1992 Corolla 4AFE 194k

The A/C on this car does not always run while idling. I checked it today and this is what happened. I started the car, and turned on the A/C, popped the hood and looked at the Compressor clutch. It was not engaging. Then I did a quick flick to the throttle and it engaged. With little more play, I figured out that the clutch engages even with a tiny flick of the throttle. Sometimes, it stays engaged for a bit of time and sometime it disengages as the throttle returns to idle position.
While driving, I figured that sometime it will keep blowing cold while idling at  traffic light and sometime not.
I think a weak electric item is causing this like the battery. Your expert opinion is appreciated.
Thanks

Answer
The first step in diagnosing an a/c problem is to check the system pressures, it may be low on freon which will cause the compressor to not engage at idle, this may be caused by a leak in the system, the only thing I can recommend is that you have a qualified a/c repair shop or the toyota dealer check the system for correct pressures and a possible freon leak, a battery or charging system problem will not cause this problem.