AC Troubleshoot

[j3002]

I have a 2008 Yaris with a non-working AC. The shop said that it's most likely a faulty compressor but I'd rather be sure before I go on replacing it.

The AC light comes on when I press the button but nothing happens. Looking under the hood, I can see the compressor pulley spinning, and I imagine the pulley should move closer to the compressor unit when the AC button is pressed?

Is there a way to troubleshoot this? I'm not very knowledgeable on car maintenance.

[shepd]

With most compressors, there should be a visible change in how the pulley looks when it is engaged. Typically instead of just the outer portion spinning, the entire shaft will be spinning.

First test is to check the pressures in the system. If they're off (typically low) the compressor will not engage to protect itself. However, if the compressor has grenaded, you will need to replace the drier and flush the entire system to ensure it hasn't thrown crap into the system that will ruin the next compressor (many warranties on new compressors require your receipt also include a new condenser, as those are tough to clean out well---you should consider it toasted if the compressor is bad).

There's some good howtos out there. I don't know if you can get the refrigerant to complete the work without a license in Finland, but there's also alternatives for that. Much safer alternatives than filling it with propane and butane, which was the old backyard mechanic method. :)

[j3002]

Thanks for your reply.

What I'm trying to avoid here is replacing the compressor and then finding out the AC still doesn't work. Maybe the compressor itself is not even faulty. Is there a control unit for the compressor and is there an easy way to check if it works?

When I took it to the shop the first thing they did was refill the system and check the pressure. It all checked out so then they figured it must be a faulty compressor. The compressor doesn't look like it's engaging when the AC button is pressed. I am most certainly not trying to fill up the system myself :) I just want to know what the root cause is.

Also, what's the life expectancy of a compressor? I see a lot of salvaged parts that are the same age as my car — would I be better off with a refurbished part? It's about three times the price difference.

[Bluevitz-rs]

It might be a faulty pressure switch or bad connection.

[CTScott]

If you can get someone to plug in a Toyota Techstream diagnostic tool, the AC ECU will report why it isn't happy.