A/C on. But, compressor doesn't kick in
 

Having issues with my A/C. I'm having some intermittent issue with my A/C. Sometimes, I will turn my A/C on and it won't blow cold air. After fiddling with the controls, I can usually get the compressor to kick in, which then I get ice cold air blowing very quickly. But, this intermittent issue is starting to really annoy me. Does anyone have had similar issue and fixed it somehow? Please let me know!

Thanks,

Have you checked if the ac clutch operates?

3 possibilities based on your description. faulty control panel. bad compressor clutch. faulty pressure switch.

Or a relay on its way out.

Hopefully this. Same symptoms as what happened on my GFs Yaris. Ended up just needing a new relay.

Just to add, the issue usually doesn't happen when the car is cold. Usually when I restart the car without giving enough time for the car to cool down.

and sometimes, the compressor kicks in minutes after A/C being on when time to time I get tired of fiddling with it and just wait until it kicks in.

Can this still be issue with relay? I really hope it's not anything related to compressor.

Relay will cost you ~$5, throw a new relay in and see if that does anything before worrying about the more in depth stuff. Or if you have a multi-meter and some basic electrical stuff you can test your existing relay.

Swap relays with one that looks similar to the AC compressor relay and see if it works.

A Toyota Tacoma/Highlander/4runner (can't recall exactly) I worked on had a issue with the AC not working at all. Turns out the relay was completely dead. I swapped it for another relay in the fuse box and the AC compressor worked. I than replaced the dead relay. I gave the parts guy the part # on the dead relay and it turns out that it has been superseded by a new part #. The new relay was a different color altogether and costed $70

The original relay that died was purple colored. I swapped it with another relay that was in the same fuse box that was brown colored but the pins aligned so I was able to use it to test if the other relay was dead or not.

The new $70 relay was blue colored.

Now I have no idea the difference between the colored relays, but if Toyota specifically colored them a certain color I would assume it was for good reason.

Had a similar issue on my Armada...A/C would intermittently work so I knew it wasn't completely dead. Ended up taking it in to the shop and they told me it was just a little low on R134a. Apparently the compressor will only kick on only when a certain system pressure is reached which varies depending on the outside air temp. Maybe just pick up an A/C pressure gauge at the auto parts store and check that before replacing parts.

Ok. So I wanna try replacing the relay and see if that works. So, where is this thing located and what would be the part number? I havn't found any definitive answer on google.

Also, it blows ice cold when it does work. So, can I rule out the refrigerant in this case?

My mechanic suggested maybe my AC was misbehaving due to slightly lower pressure in the line. So, he did evac and recharge. It didn't solve the problem. But, now the symptom is different. Now, AC compressor kicks in at cold start, Then few seconds/minute later, it shuts off. Only way I can get it to work again is to turn the AC off for awhile. Then, it will kick on again for few seconds. So, now I'm thinking maybe it's something related to actual AC components and not the relay. Any ideas?

Get a new mechanic. Sounds like he is just throwing parts at it, instead of actually diagnosing.

That said, could be something like the high side pressure is too high, causing the system to shut down. There is a switch that monitors high side pressure and if it exceeds X pressure, it will shut the system down. But, if your mechanic did diagnosis correctly, he likely would have seen this issue on the gauges. But, maybe not...

i am going to post this a second time because its obvious you were swayed in thinking it was a relay issue.
3 possibilities based on your description. faulty control panel. bad compressor clutch. faulty pressure switch.

Doesn't seem to sound relay related now.

It would really help if we knew what the high and low side pressures were.