Waht is the wire with a purple connector?
 

I have come for some basic advice. I have a 2001 Cavalier that I bought when I was a teenager. I was hoping to to reach at least 100k miles on it but I am not sure I am going to get there due to crazy issues that are popping up. By the way, I live in the city and that is why I haven't reached 100k miles in 12 years.

Anyways, my car starting hesitating when starting up so I decided to change the battery. Now, changing the battery is such a simple procedure that I decided to use my local PEP boys. They ended changing engine belt too. After the service the car started up fine but the AC was not getting cool anymore. It could have been a coincidence but I brought it back to PEP boys and asked them to take a look. They reported that the AC needed to be charged and a wire replaced - total cost of over $400.

I am not spending that - plus I don't trust PEP Boys because the AC worked fine before getting my battery changed. I bring my car home and look under the hood just to make sure nothing is completely out of place. Sure enough there are some screws missing, but not sure if it was PEP Boys who removed them. One thing I am sure was PEP Boys though, is a wire that is obviously unplugged.

So here comes my question... anyone know what this wire is? Can I drive the car without having it plugged in?

http://paulpallas.com/public/wire.jpg

Looks like a plug for an AC pressure switch. The AC will not work without it plugged in. If you plug it in and the AC works again make sure you go back and complain to the store manager as they were trying to rip you off.

Thank you so much for the response. The diagrams are great. I am going to work on the car (haha plug in a wire) tomorrow morning. I'll let you know how it goes.

Unfortunately, after plugging in the wire - the AC still does not cool down. I do think there is something wrong w/ that that wire though. If I play around with the wire (just moving is slightly) while the car is running with the AC on - the engine starts responding (getting louder or quieter). I am going to bring it into a mechanic sometime next week.

Again, thanks for your help - I really appreciate it.