Hello J,

You do not have to add the switch, but it is a nice safety factor to extend the life of the compressor. It is something you can add later or now.

No need for a diagram. The wire you are after is the one goes to the clutch on the compressor. Mine is a green wire but not sure on your year. Bottom line is find the wire that connects to the clutch and follow it to the plug. You want to snap the plug apart and snip off the wire about two inches back on the engine harness side of the car, not the side that goes to the compressor. You will need two pieces of wire (four to five feet each) 22 or 24 gauge, two spade lugs, and a couple of butt splices (red). Use one butt splice to connect to the wire you just cut. Splice the connector end you snipped off to the other wire. Tape or shrink tube the two butt splices and then plug the connector back onto the compressor.

Since both wires are going to the same place, pull both wires down the drivers side fender to the front of the car, then across behind the grill and in front of the evaporator coil to the other side. You can tie wrap to the center brace where the horn are or to the hoses, just avoid sharp edges with the wires. There is a hole where you can pull them through to the passengers side and then up where the dryer is located. Trim you wires to length and then crimp on both of your spade lugs and plug them into the switch on the dryer. Does not matter which one goes where by the way.

You are done installing the switch. If the pressure falls below the switch set point, it will open and keep the compressor from running.

To charge up the system you will need to put a short jumper across the new spade lugs you just installed on the new low pressure switch. That is so the compressor will run until the pressures go up. Slip the lugs back on when you finish the charge and you should be good to go.

Regards,

Paul