My 2001 maxima a/c does not cool. checked pressure is full, compressor does not engage, relay is ok, when relay is taken out and bridge with a wire compressor comes ON and a/c cools. can someone help pleaseee.

AC clutch has to be energized for the compressor to turn and cool. Check out the thermostat as well as the low pressure cut off switch, relays for proper operation.

If you connect the 12 volts to the hot side of the clutch it should engage - if so that indicates that the issue is caused by some electrical item in line with the circuit that powers the clutch.

The accumulator or dryer looks like a long cylinder, it has a pressure switch on it and two wires attached to it. pull the wired molex off, with the ac set on max cooling, jump out the two wires with a wire or paperclip, if the clutch on the ac compressor engages, check the cab to see if its cooling, if it does cool the switch needs to be replaced, if it does not cool, you may need freon, and there could be a sign of a leak in your system, that can be best checked with ac manifold guages. the low pressure switch is there for safety if the canistor or accumulator is low or has no freon the switch opens up and keeps the clutch from running so that the compressor will not burn up. good luck!

Check for broken wiring, blown fuses, possible bad relays, and look at the pressure switch. Some systems have a high pressure switch (some have a low pressure also) that prevent the compressor from running. If it is faulty or damaged, it could be preventing the compressor from running. Wire damage could be possible with front end damage.

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

disconnect battery for a few minutes then hook it back up. Hope this helps Tim

Check voltage to pressure switch at relay and at fuse. you may have a bad electrical connection bad wire or blown fuse. Also check the clearance between the clutch and pulley, you didn't say if compressor clutch pulling in. Might have multiple problems, check switch at dash as well. Last year I had A/C prob.s and found out GM had problems with the fan cool/heat controller on my Yukon XL. Replaced it free, but all other work was at cost. Hope this helps.

Is the solenoid clutch holding on to engage the compressor, if not the relay or the fuse or the sitch is not active. check the connection to the relay.
If solenoid is turning the compressor then there is no pumping and so the cooling does not happen.It can be failure within the compressor, needs an overhauling .

take the pressure switch connector off and jump connector- if clutch engauges you either have bad low pressure switch or are low on freon.

you havent check the pressior of the compressor make sure is full loaded

Check the connections on the plug going to the compressor clutch and on the pressure switch on the low side. Also check the gap on the clutch. It may be too wide after where to engage correctly. Good luck.