1999 Cherokee sport. With the ac on the ac compressor keeps cycling on and off every few seconds. The pressure goes up with the compressor off and down when it's on. Any suggestions. Does that mean a leak somewhere? Or could it be the clutch?

 

Cycling quickly means it is typically low on freon. You can get a recharge kit at any parts store.

 

I was filling it when I noticed it was cycling. The pressure goes up almost to the red so I was worried about over filling it so I stopped. It goes way down when the compressor kicks on. Should I keep filling it

 

Keep filling. You are supposed to measure pressure when the compressor is running. Only fill while the compressor is running. You can bypass the cutoff on the top of the evaporator if your impatient like me.

 

Ok I'll fill it. Thanks for the help

 

You most likely have a leak. Fill it up but also add some dye. If it goes low again you can find your leak with a black light. If you're lucky it will just be an o-ring.

 

It could also be an extremely slow leak that took 100k miles to leak out. These are old vehicles. They often need refrigerant at this age. Yes if it is gone in a year or two again, it would start looking for leaks.

 

Thanks for all the info and help. I'm gonna fill it and see what happens. I don't have a black light but I'll see if I can get one and get some dye

 

I filled it to the green part of the pressure gauge on the can. The compressor stayed on and the ac is cold. There's still room for more so I'll get another can with dye in it and see if there's any leaks.

 

dont waste money, use it like it is and look for leaks. cuz when you find a leak you will have to loose the rest of the freon and fix the leak.

look at all connections, lower part of condencer and the heater box water drain. it will be a neon green if there is a leak.

 

Thanks myjeep