2007 Toyota Highlander Blinking A/C Light

I have a 2007 Toyota Highlander (130K miles)
Recently, the A/C stopped working.

What happens:

  1. With the car running and A/C off, turn on A/C
  2. A/C starts blowing and begins to be cool
  3. About 10 seconds later, the LED on the A/C control knob starts to blink and stops blowing cool air

A few diagnosis items:

  1. Between steps 1 and 2 above, putting a PSI gauge on the low side port shows about 40 psi, which I believe to be normal
  2. After step 3, the PSI gauge shows about 130 psi, which I think is way too high
  3. Replaced magnetic clutch relay with no improvement
  4. When step 3 occurs, a light grinding noise occurs but then stops
  5. No diagnosis codes on the OBD2 port

Any ideas?

Thanks for your help

Unplug the electrical connector to the compressor clutch.

Start the engine and turn the AC on. Supply 12 volts to the compressor clutch connector.

Let the compressor run until you can determine if there’s a problem with the compressor or the compressor clutch.

The 140 PSI you saw on the low side when the compressor stopped running is the normal static pressure, depending on the ambient temperature.


The A/C light blinking is telling you the A/C control module has detected a problem. A typical OBD2 code will not be set for this. You’ll need the A/C control module accessed for codes separately. There are a few sensors in the A/C system that the module monitors. The problem is most likely with one of those. However, without the codes, it would be difficult to determine the problem.

Great. Thanks for both of your responses.
How do I access the A/C control module codes?

What is ur high side pressure when a/c is working?

“How do I access the A/C control module codes?”

The dealer and some shops have the full suite of code reading programs. You have to ask.

I will take a look this weekend at the high side pressure.