I am changing the ac compressor on my 99 1500 silverado v-6 and noticed the factory compressor on the truck has a sensor on the back of the compressor but the new one I just purchased does not. What is this sensor, what does it do, and do I need it because the new compressor has that area blocked off. Thanks

 

Yes you need the sensor. There should just be a snap ring holding a plug in the hole on the new compressor. Just use a pair of snap ring pliers to pull it out and the same for pulling the sensor out of the old compressor. Be careful as sometimes there can be some pressure buildup so dont have your face directly over the hole when you pull the plug out.

 

It is the high pressure cut off switch. It does need to be swapped over. As said before just remove the snap ring and it will come out.

 

+2 with these guys

 

Thanks guys, replaced the compressor today. Sensor was removed easily after taking out the snap ring.