I have a (relatively) newer central air unit. It's a lennox about 4 years old. Yesterday it just stopped cooling. Had been fine previously. I did the normal checks... batteries in thermostat, make sure I hear it "click" to turn on air. Went outside and the fan outside's blowing... but wait... I hear about every minute it's trying to kick on the compressor. I pull off the cover panel and manually press the magnetic switch. One side turns on the fan which is fine. The other side tries to kick on the compressor.

OK... that out of the way... help, please? How do I trouble shoot from here? The connections "appear" to be good on the compressor. But I know there's supposedly some other relays I should check, supposedly. Also, the possibility of putting in a hard start kit. I would love some decent advice as to whether a hard start kit is necessary or if there are other things I could check.

Thanks.

It could be the run capacitor for the compressor
It could be a damaged wire (look for disconnected or burnt wires.)
It could be a defective compressor.

There are many more items it could be but I do not believe a hard start kit is going to make a difference since the unit has been running for 4 years without one.

Thanks for the help and quick response. It actually turned out to be that it did need a hard start kit. $300 lesson. Now I know to get one and have it ready for the future. :)