89 FB w/ 305 tbi all stock.

just bought a new a/c comp. and i went to change it when i noticed there were 2 plugs on the back of my old compressor and only 1 on the back of the new one. one is a flat 2 blade plug right behind the clutch and the other is a round 2 prong on the back of the unit (this is missing in the new one) what are the 2 plugs and can i just jump it? the new comp. has an empty spot for it with a snap ring and the old comp. plug is held in by a snap ring. do i just swap it?

any help is thanked

 

That is the High Pressure switch. You need the 2 wire plug. any auto parts store will have or get one. Just take the single wire and attach it to one wire and ground the other. I just had to do this on mine, I switched to R4 compressor. The R4 units have 2 or 4 wires HP switch. My new compressor had no switch. My old one single wire. I don't know if the HP switch interchange. Remove snap ring pull the old one out and see if it works.