A/C pressure transducer

Good afternoon.

There is no uploads on your post. Try reloading them.

The transducer should have voltage. Can you verify that voltage?

When you checked the relay, was there power at two terminals with the key on?

Also, I need high and low side pressures.

I attached a wire diagram for you to view.

Roy

Do not see an image, but that is a variable resistor you are testing. It should show a resistance value between all three terminals. If you are testing the connector end you should have one pin that is ground, one pin that is "open" (that will be the signal out of the switch) and one that shows a voltage (5 volts) with the key on.
However, there is no specification for it as the testing is done by reading the voltage it sends to the body control module using a scan tool.
If you want to try testing the voltage at the sensor you can. Use a thin probe and test the voltage off the signal pin by back probing the connector. A voltage of over 4.27 (pressure over 414 psi) or under.35 volts (below 35 psi) will keep the system off. If you do the math you can use the voltage to get a rough idea of system pressures, basically every tenth of a volt equals approx.10 psi in the system.
So your 105 psi should show as about 1.05 volts.

As for being connected to the computer. Yes, very connected. The system uses the dash control to tell the instrument panel that you want AC on. That signal is then sent to the body control module which reads the pressure sensor and informs the Powertrain Computer of the request. The PCM reads the pressure sensor and exterior temperature and turns on the AC clutch. It then monitors the pressures and temperatures in the system to cycle the compressor on/off as needed.

However, your resting 105 psi seems high. A general rule of thumb in an R134A system is that the "resting" pressure is roughly equal to ambient temperature, however if the engine was running or out in the sun it could read higher.

Whenever you wish. No appointment needed.

That pressure should be okay if the temperature was high 80-90 degrees.
Yep, relays can be a pain.
The numbers on 99% of them will be the same 30, 87, 87A, 86, 85 on a SPDT relay
85 and 86 are the coil, 30 contact pivot, 87 normally open contact, 87A normally closed contact. However, there are versions with diodes or resistors across the coils as well as some with diodes across the contacts.
Was going to suggest a bad relay as that is a common failure item. Glad you found it and thank you for using 2CarPros. Return anytime with your automotive questions.