My compressor clutch won't engage when i turn the A/C on. I've tested the relay, clutch, wires, and everything checks out. A/C runs fine if i bypass the relay and power it directly but i dont want to leave it like that. Hopefully i can get some help figuring this out because i can't think whats causing it. Thanks.
Did you check the alternator as well? i think it could be that or you need a new battery
I did think it could be any of those two but after testing them out i cancelled them out of the equation. the battery keeps a stable voltage with the car on and off : the alternator is able to keep the car running on its own even when i disconnected the negative battery cable.
You should never disconnect the battery when the engine is running, damage to electronic components can result. Assuming the relay doesn't even energize and fans don't run you need to trace out the circuit that triggers the AC. I don't know if on the Neon that's a computer or whether it's operated directly from the HVAC controls. Since you say AC works fine when hot-wiring the compressor you have refrigerant, but the low-pressure cutoff switch or its wiring may be defective. Also check for other switches and sensors that can shut down the air conditioner.
Also, when hot-wiring the compressor never let it run more than a second or two unless you are absolutely certain there is refrigerant in the system. Running it dry for any length of time will destroy the compressor.