My AC compressor isn't engaging. I've checked the fuses and relays in the engine bay. Anything else I should check before I take it for service on Monday?

 

Its probably low on refrigerant. The cooling system has a low limit sensor that shuts off the compresser if there isnt enough refrigerant in the system for safety reasons to the compressor.

 

Had it checked today. Refrigerant is fine. no power is reaching the compressor. I'll take a look around the SJB, it's been raining like crazy around here due to the stupid hurricane. I just hope water didn't get inside.

 

There are two fuse boxes, one in the kick panel and another under the hood. The one in the kick panel is like a 5 amper. It's for the switch. The underhood fuse is for the main power.

 

Checked the SJB. Both fuses fine and everything is dry. next I'm going to pull out the dash and check the AC controls.

 

Don't rule out the pressure switches. Just like a relay these mechanical items fail. What were your high and low pressures and what was the OAT?

 

I dont think ambient temp or high side pressure would be relivent . Do to the compressor not being on. Im not sure of all the components involved on a car a,/c so a schematic would be nice. I think your on the right track tho, either your switch or one of the pressure switches could be opening the circuit when it shouldnt. Also wiring and connections are as problematic as anything else.

 

Ok, so basically I don't know what happened. A/C just started working again this afternoon. Not that I'm complaining, but I'd still like to know what was wrong with it.

My only theory is that it's related to the massive amount of rain we had last week courtesy of everyone's favorite hurricane, Sandy. Now I need to fix the horn because one apparently has water in it.

 

Hi Side pressure would make a difference with the AC off since both High and low sides should be equal when the system is off. If they are not equal, that could be signs of a clogged passage (like the orifice valve).

OP: Either invest in an A/C Manifold guage set and learn a little about troubleshooting automotive A/C or take it to a shop. Don't just start throwing parts at it.