I need to recharge the AC system after replacing the engine. The system is totally empty and the compressor will not come on. Reading the Hayne repair manual, it is saying to jumper the wires on the connector that plugs into the sensor on the low line. There are 3 wires in that molded sensor connection. Do I jumper all 3 of them togthere? I have tried to jumper 2 of the 3 in every sequence but cannot get the compressor to engage. I have checked the fuses and they are good. What am I doing wrong, am I not understanding the instructions? Oh, and I have verified that the compressor has the wiring harness connected to it.

 

You have to jumper all three together. Running the compressor with nothing in there will more than likely burn it up. When recharging from empty, you need to pull a vacuum on the system, and then fill it. I would also put some oil in there to lubricate the compressor. Some refrigerant cans come with it already, but I would check what kind it takes before you do add it.

 

+1 on what 02 Stang said but I will add in some. If you had you system down and open for awhile (More then a day) your dryer receiver has maxed out its limit of moisture. Just like it sounds the dryer pull water out of your system but if the system is left open it will pull the water from the air.

The reason you need to use a vacuum pump on the system is there can be no moisture in the system. If there is you will form ice in your orifice. If that happens your system will never work right until the dryer is replaced and you redo the vacuum and recharge it. The Dryer is there to trap any mositure the vacuum pump missed.

Also on the oil. If your system was drained slow thru a set of gages or you sat there and held the schrader valve while the system bleed down you most likely will not need oil. If you craked a line to drain it. You will need oil. I always error on the too much is better then not enough side of this debate. Just like 02 stang said.

 

Thanks for the info. I don't know how the air conditioning was released, it was empty when we loosened the hoses. Sounds like it might be better to let someone with the proper gauges and stuff recharge. I guess I will have to replace the dryer, I left it open for several weeks. Air conditioning is something I know very little about!

 

On my 95 Camaro with 3.4l I have the same switch, 3 connector on the high pressure line. If I jump the 2 pins that are beside each other in the connector the engine shuts off. I am guessing this is not supposed to do this?? What would be causing it to make it shut off?

 

maybe the compressor is seized, thus bogging the engine til it dies

 

No its fine. It never engages the clutch, but the compressor spins nice and free by hand.