Yaris A/c blows cold air and then after a while it blows hot and cold again.

[Pong1975]

Hope someone will help me regarding my a/c, it works at start then after a while it blows hot air and then cold again like a cycle process..

[SirDigby]

you prob have a low charge. you need a set of manifold gauges to check system performance. if the pressures are correct, then you might have compressor issues like clutch clearance or valve issues. it's prob best to take it to a professional if you don't know what you're doing or have the proper tools.
do not got to autozone and just start spraying junk into your system.
I recommend fixing it correctly or not at all...

[Kayo]

I had this issue and it turned out to be just the ac system needing servicing. It would blow cold while driving but once I came to a stop or moved in traffic it was warm again.

[bassmannate]

Had this problem with my Corolla after having the radiator replaced. Turns out that they didn't plug the radiator fan back in so when I came to a stop, the fan couldn't come on and cool things down. Only had cold air while moving.

[jra]

There will be a sight glass somewhere under your hood, follow the AC hoses from the condenser to the firewall and you will find it. On a warm day turn your AC on high and wait till it starts blowing cold air, open your windows, make sure the compressor clutch is engaged, the shine a light into the sight glass and look for bubbles, if you see a lot of bubbles it needs to be charged, if clear or only a bubble now and then, means something else is wrong.