Where is ac compressor relay. Is it k9,k12 or which one

Pull a relay out and use paper clip to jump. Usually cross corner. Watch compressor clutch and see if engages when key is turn ahead. Don't start car. If it does good. Now take alligator clips and check relay. Clip each wire to negative and positive battery post. Then clip negative to negative relay pin. And touch positive to correct pin. If it doesn't click do it another relay so you know your doing it right. If determined relay is good. And your compressor clutch did engage when testing it. You are low on freon.

I passed this question the first time I read it, so I will take a stab at it now.
The fans don't come on until the compressor has pumped the freon pressure up to say 150 or 200 psi. And the compressor clutch has to have voltage to engage the clutch.
I wonder if the clutch is going and needs 14 volts instead of 12 to engage ? Or the relay that powers the clutch ?
Speeding up the engine would increase voltage from the alternator.
This is assuming the serpentine belt is tight and everything else is working correctly.
I think I would swap the relay with another and put a meter on that circuit to the ac clutch to see what it takes to engage it.

OOPS ! Now, it sounds like the A/C relay is constantly on. In the power distribution box by the battery, try swapping another relay for the A/C relay (which turns the compressor on), and see if it now stops. If so, buy a new relay. Good luck.

If all you get is hot air there are several possibilities. The compressor is driven by the serpentine belt and is engaged and disengaged by an electric clutch mounted on the compressor drive pulley. With the engine running, have an assistant turn on the AC while you observe the AC compressor clutch. If the clutch engages, you can be reasonably sure that the system has freon, and the electric circuit is OK. If the clutch doesn't engage, which is the most likely situation, either you are low on freon, the AC clutch relay is inop, or AC compressor fuse is open (blown). A search of Google images will give you the location of the AC relay. You can pull out the relay, carefully remove the cover, reinsert the relay, and engage the compressor clutch by manually closing the relay contacts. Warning: do this only for a second or two in order to see the clutch engage. If the clutch does engage, then you are probably low on freon. There is a safety switch that prevents the clutch from operating if there is not enough freon in the system. Hopefully, this is the case. Go to Walmart and get two cans of r-134 and the inexpensive kit, and following their instructions, charge your system. If this is not the problem, you'll need a set of AC gauges and the skill to use them. Hope this helps. Dano

Since you know that the clutch must engage in order for the compressor to operate, then there are most likely one of causes. The first is low or no freon in the system. The a/c system has a pressure sensor mounted in the low( return) side hose that prevents the clutch to engage if the freon is too low. The second would be the a/c fuse or relay faulty, preventing the clutch solenoid( a 12 volt electrically operated solenoid) from engaging. And the third would be that the clutch itself is bad because the solenoid wiring has broken. I suggest that first you locate the a/c clutch relay in the relay panel, remove the relay, carefully remove the plastic cover from the relay and reinstall the relay. The clutch should engage the compressor when you manually close the relay contact with your finger for one or two seconds. If the clutch does engage, your electrical circuit in ok and you are probably low on freon. A half of a can of r-134 in more that enough to operate the pressure switch. If it doesn't engage, check the a/c fuse or the clutch solenoid itself. Get back to me and let me know how things went. Dano

When your R-134a runs too low it will NOT engage the compressor. You need to refill your a/c system before the clutch will engage, I also suggest finding the leak.

CHECK AC COMPRESSOR CLUTCH SHOULD BE ENGAGED OR RUNNING WITH AC SWITCH ON POSITION.IF NOT CHECK AC COMPRESSOR CLUTCH FUSE AND RELAY.IF BOTH GOOD AND POWER IS GOING TO AC CLUTCH.YOUR CLUTCH IS OPEN.IF ALL LOOKS GOOD YOUR AC LOW PRESSURE SWITCH IS BAD.COMPRESSOR SEIZED OR YOU HAVE TOO MUCH MOISTURE IN AC SYSTEM.

the A/C has an inhibit switch that prevents the compresor running without the correct gas pressure (the gas also carries its lubricant) there is one wire that goes to the front of the compressor, this should engage the magnetic clutch when energised, this bypasses all safety controls so do not run it like that. If this is what you tried then the clutch has failed.

Check A/C compressor relay. When you say it seems to be full of gas(freon) have you actually put a pressure gauge on the system? If the pressure is too low, the compressor will not engage. If the compressor relay is functioning, check for power at the compressor clutch. If it has power to it and it still is not engaging, the A/C clutch may need replacing. It is usually almost as economical to replace the complete compressor with clutch installed than to just purchase a clutch. Keep in mind if you replace the compressor you should also replace the receiver/dryer also referred to as the accumulator.

It's low on freon