This could be a couple of things but let's start with how it works.
If you look at the wiring diagram, the relay is powered on pin 30 and 86. So we need to make sure you have 12 volts on both wires when you have the key in the on position.
Next when the A/C is supposed to be on, the PCM grounds the relay by applying ground to pin 85 which energizes the relay and closes the contact inside. This will then complete the circuit from pin 30 to 87 which sends power to the compressor.
So, what I would do is check the power on 30 and 86. Then check the ground on pin 85. You do this by putting your red meter lead on a 12-volt source like the battery. Then put the black lead on terminal 85 and turn the key on and AC on. Your meter should read 12 volts.
If it is not, then the PCM is not commanding the relay on.
At that point, it could be a PCM issue, but it could also be a pressure issue or a pressure sensor issue. So that means we need to check and see what the actual pressure is in the system.
If the pressure is not correct when you jump the relay to get the compressor to come on, then we need to set the pressure correctly and see if the compressor will come on.
If it still does not, then we have a sensor or PCM issue.
So, let's start with all this info and then if we get there, we can figure out if we have a sensor or PCM issue.
Saturday, June 18th, 2022 AT 7:55 AM