A/C Wiring part

I have a 2001 tahoe,X Police vehicle, Went 4 wheeling, got a part wet, the ac compressor had locked on, now it will not work. I can manually activate it however not on it's own. I have traced the problem to a small sealed black object under the hood. It has 3 wires, 2 plug into wires on the a/c wiring the 3rd runs to a relay next to it. To activate the a/c the 3rd wire puts a graound to the relay turning on the compressor. The dealer says it's not factory wiring. I have pictures of this item f needed. Can anyone help??? PLEASE!!?? LOL

sound like something the police added for some reason factory wiring has a compressor relay in the under hood fuse center not next to the compressor.

Ya, but I don't know what it could be. Wish I had one to look at to see what the factory wiring was. Then I could put it back. This will suck in the Missouri Summers, not to mention the compressor runs with the defrosters.