2010 Prius AC only turns on through defroster

I'm not sure if it's industry standard, but I know at least some cars silently default to defrost mode every time you turn off your car. The idea is that if there's a failure, you'll at least be able to drive safely.

If something happened to cause the louvers to get jammed into place (stuck in defrost mode), the fix might be as simple as finding and removing the jam/debris.

Simple, but not easy.

Of course, I could well be barking up the wrong tree, here. At least it's something to look into.

 

I don't know if that's what other people call it but I'm referring to the internal mechanism that changes which ducts the air is getting pushed through.

 

Blend door actuators

 

Sounds to me like you've nailed it, the button. If it were mine I would pop the control panel out and see how hard it is to clean the contact surface behind that button. Toyota discourages that, but I've taken my chances before with good results.

 

I’m thinking your AC only works when you push the front defog button; is that right?

 

While the button theory sounds reasonable, the Auto mode should run the compressor as long as the temp is above the default 68f and a dealer has not intentionally turned off the feature. It drops out of Auto if you adjust the fan speed. I would assume your outside temperature is displaying accurately.

 

I would suggest to check your fuses to see if any of the ac ones are blown. If they are the Prius may be putting it into some kind of default safety mode or something.

 

If the A/C will work in defog mode, and the A/C green light works during the self test, and you can't make the green light turn on and off by pressing the A/C button (while the blower is on), then the button is a suspect and there aren't many others.

 

But he can't just change modes either, right?

Does the recirculate button work? What about the one on the steering wheel?

 

I get it—we're reading the original post in completely different ways.

Some of us are reading "the AC" as meaning "the whole HVAC system", and "the AC can only be enabled through the defroster" means the system can never be made to blow any direction but up.

Others of us (me included) are reading "the AC" as meaning "the part of the system that refrigerates the air", and are reading the post as meaning that the blower, the heat, and all the outlet directions work fine, but it just doesn't refrigerate the air (except when defogging, because it's automatic then).

So maybe the thread will seem less chaotic if the OP clarifies which reading was meant.

 

If you can find a control panel from a recycler for a price you're willing to gamble, I would just pop out the one you've got and pop in the replacement and see what changes. If that makes a difference, you also then have the old one out, and may easily see how it can be further disassembled to spot the problem.

If popping the old panel out and a replacement in takes you more than two minutes, it will only be because you're doing it the first time.

I would lean toward trying a panel from a recycler because the new price is a bit salty.

 

Angle of the photo. The horizontal button-row runs across below the liquid-crystal display.

If even a recycler unit is cost-prohibitive, you still have the $0 (possibly) option of taking out the control panel you've got, and inspecting it to see if you can disassemble it without damage and clean up some button contacts. If my hunch is right, this may work. However, the easy swap-with-another-unit gives you a quicker and less-risky way to find out if my hunch is right, before you try to disassemble the only control panel you have.

It goes without saying that Toyota doesn't give any sub-assembly-level repair instructions for that panel; they only expect it to be replaced as a unit. That doesn't always mean it can't be disassembled or repaired, only that you're on your own to figure it out. If it gets damaged in disassembly or turns out hard to reassemble, then the cost isn't $0 anymore.

But there are threads on here from appearance mavens who have taken theirs apart just to change the color of the backlight LEDs, so clearly it's not prohibitively hard.