A/C not blowing cold air

I thought about that earlier but this is a dual pressure switch which means it shuts down when pressure is high or low. They are normally 3 wire sensors which means it sends a signal to the control module. However, looking at this again that is not the case on this vehicle.

Your pressure switch is an on off switch so you can jump it. Basically it looks for 12 volts or 0 volts. So just disconnect it and put a wire between the two terminals and then turn the ignition and A/C on. It should come on. This confirms the sensor is the issue.

Great idea and glad you mentioned it to make me look again. That's what I get for assuming.

That is correct. Basically they are using this switch to control the fan speed as well to keep the engine cool and air flow over the condenser.

This is progress. This is showing that the module is not grounding this circuit.

Here is what you should have: At the control module, it needs to see 12 volts on pin 1. This shows that the pressure is correct and it is ok to turn the compressor on.

Then the control module will ground the relay on pin 9 and you will see 0-1.5 volts at the control module on this wire. You have battery voltage which shows it is not grounding the circuit.

You have 0 volts on pin 1 so it is cutting the compressor off which is why the two wires going to the PCM are not reading the correct voltage either because this is the AC module telling the PCM that the compressor is off.

If jumping that switch does not cause the compressor to come on then we are back to the control module.

What I would do from here is just make sure you don't have a wiring issue from the switch to the module by jumping the switch again and then check voltage at the module on this wire, Pin 1. You should have the same voltage that you do at the switch. If you do then the module is the issue.

Another way to confirm this is to just leave everything connected and jump 12 volts from the battery directly to Pin 1 of the module. If the compressor comes on then it is not getting 12 volts and you have a wiring issue.

Take a look at this below. Please let me know if you have other questions and what you find. Thanks

Don't worry about the wire color. That could be an issue with the wiring diagram. They often changed the color wire when the run out of one, they switch to another.

Let us know what you find when you get to it. Thanks

That is excellent. You are exactly correct. If you look at the chart and wiring diagram below.

You need 12 volts at pin one in order for the module to know that the pressure is ok. If you jumped the switch and then checked voltage at the module using the modules ground and you have 12 volts on your meter then you verified the entire circuit.

If the module has 12 volts on pin 1 and it still does not come on then the module would be the issue.

However, you appear to have an issue with the switch as well.

The jumping of the switch is a clear and simple test. If you have to jump the switch in order to get 12 volts to the module then the switch has failed.

If it were me, I would replace the module and then jump the switch again which should cause the compressor to come on. If it does, replace the switch. However, if you want to put the switch on it now, I would understand because this is a simple on off switch based on pressure. So either it is closed or open based on the pressure and if the pressure is correct and it still is open then it is faulty.

Normally yes. However, when you jump it the compressor should come on if it were the only issue. All the switch does is provide 12 volts to the module which tells it the pressure is not to low or high. So if you not only jumped it but then applied 12 volts to it and it still did not come on then we have another issue.

Let us know how you make out with this. Thanks