plug on AC compressor

I'm changing out the AC compressor.  Old one has 2 electrical plugs - one in the front and one in the back.  On new compressor, there is no connector in back, just metal plug held in with retaining clip.  Why is there not an electrical  plug in the back?

Hi chillin!
Would help if you said what type of car you're working on, but for the most part, the front connection is for the clutch operation. The read connection is for a switch. What's the switch for? That depends. Typically, the switch is part of the ground circuit for the clutch. If you bought a reman (sounds like that) they never put the switch in because it could be 1 of several different ones.

Did you keep the old compressor? (Hope so) The intention is that you remove the switch from the old one and install it into the new one. Because there are so many switches and variations, it's impossible for the factory to put the right one in.

When you flip the switch, you will need a good pair of snap ring pliers. You should also have a new o-ring for the switch. I would not trust the o-ring in the new compressor as it's been sealing the plug. Be sure to lubricate the o-ring too. Whatever you do, do NOT just ground out the wire. The switch is either part of the ground circuit or a pressure cut off... but either way, it's a safety for the compressor. Operating without the switch is asking for trouble.
Not trying to jump on you here, but if you're doing the compressor, there are other items that should be replaced with it. However, it really depends on the reason for changing the compressor.

Would be happy to help with a little more info.
Hope this helps!
You may also want to read this info:
[url="http://autoacsystems.com/_faqs/detail/compressor.html target="_blank"]Replacing your auto A/C compressor[/url]

Thanks MAX.  Yes.  I took the old and new back to the parts store and they helped me change it out.  Its a 99 blazer.  I also had intentions to change out the accumulator, but the aluminim tube on the condenser side of the accumulator was turning with the nut, and the tube is slightly kinked.  Good thing its not summer so I have time to get this fixed!

how did you kink the tube?

Hi chillin,
Hold on a minute. You could have a bigger problem here. The tube is actually part of the evaporator. I am telling you know, you don't want to break it. They are not cheap and they are a lot of work to install.

Before you go any further (and I realize it's not hot right now, but just in case) try some 'tricks' on the nut. If you have oxy/accet torches, use heat on the nut. It will fry the o-ring, but that will have to be replaced anyway. If no torch, use some good lubricant that you can apply a few days in advance. Let it soak in. You really don't want to mess up that evap.

Hope this helps. Let us know if you need any other info.