a/c compressor relay switch???

My 96 astro has a attachment on the end of one of the pulley wheels that the belt goes around. About every 10 seconds during idle and while driving a little relay switch kicks on and this attachment spins with the wheel, then after about 7 seconds the switch clicks and it stops spinning.
My problem is that when driving and it clicks on, the van seems more sluggish, and when it kicks off it feels fine. It seems to be in the a/c compressor area, but this happens when no heat or a/c is on at all.

If anyone knows anything about this it would help, thanks

Are you sure the AC isn't on? It sure sounds like the AC compresser clutch is cycling on and off quickly. This is caused by a low freon level in the system. Does the AC blow cold air?

The a/c does blow cold, but I realized that the relay is kicking on when heat or a/c are on. Any idea if the compressor is connected to the power booster for brake and steering, I constantly have a steering whine, not loud but noticable.

One of the pulleys drives the power steering pump, but it doesn't have a clutch to start and stop the compresser like the AC does. The power steering pump goes all the time the engine is running. It may be low on fluid if you are getting a whine all the time. It has a dipstick to check fluid level. It also powers the hydraulic booster for the brakes.

I changed all the steering fluid a month ago to no avail. I will try to top up the refigerant anyway and see what happens. It seems to me I may be looking for it too much when the compressor kicks on, since it's going to rob a little power from the engine.

the compressor also comes on whenever the defroster is turned on, summer or winter. maybe there is something wrong with the selector switch or one of the vacuum lines that are connected to it.