I just had my 98 XJR engine replaced - I put in another 98xjr engine (yes Nikasil again, I know...I just can't get enough of the fast engine warm up) - good compression, tensioners had already been recently replaced, runs like new.

During the engine swap, there was a seized bolt on the A/C compressor, so I had it replaced, recharged etc. Now the compressor won't kick in, making the A/C useless. I've already replaced the A/C compressor relay.

Anyone have any guesses as to why my A/C compressor won't kick in? It's getting hot here in the midwest again.

 

The most common problem after the fuse and relay is the pressure switch. You may either have low charge or a bad switch. The switch will not let the compressor run if the pressure is out of range. Most AC issues beyond fuse and relayare not really a DIY project, let a pro look at it.