I just purchased a 96 a day after I got it the car alarm started to sound after about two time the battery would die. We charged the battery and go to looking. Found the relay in the box to the left for the a/c was jumped with a wire. We purchased a new relay but now the a/c will not blow cold air. We jump the relay and it will freeze you but kills the battery. We also found that the a/c had way too much pressure on it so we release some of it but a/c will not blow cold with the relay in place. Are we missing something?

 

By having the a/c relay out and jumpered, power is keeping the a/c compressor clutch energized all the time, even when the car is turned off.

The relay acts like a switch compressor clutch. So when you put in a relay, you now have a problem of why the relay is not being energized. This could be a bad triple pressure switch. It could be other things, but the pressure switch seems most logical. The previous owner didn't want to pay the repair costs because they were selling the car.

 

Could you tell me where the triple pressure switch is? or where to start to look for it.

 

Of course it's under the hood - on the drivers side. Start at the battery. In front of the battery is a box with various relays. Look down in front of the relay box and you will see a round aluminum canister, smaller than a soup can. The canister is called the "liquid tank". The top of the canister has the triple pressure switch screwed into it. There is an electrical connector with 4 wires plugged onto the top of the triple pressure switch.

If you unscrew the triple pressure switch without evacuating all the refrigerant, it will come blowing out in your face.

If you want, you can look at the block diagram for the a/c system.
page 38 for manual climate controls.
page 90 for auto climate controls.

http://boredmder.com/FSMs/Nissan/Maxima/1996/HA.pdf