I know my compressor works because when I jumper the 30-87 connections on the relay, it kicks on as it should. I checked and recharged the R134 in the system, it wasnt too low, just needed a little bit, and the air was working as it should, blowing cold air with the relay jumpered. However, when it is not jumped, you can see the clutch kick on, then right back off once or twice, then it just stays off. The outside temperature is also in the mid-upper 90's every day with 105-115 heat index.

Why doesn't the compressor kick on without the relay jumped as it should?

 

Have you put gauges on it? What kind of pressure are you dealing with? If the pressure is too high or too low it could have another problem. If your pressure is right you could have a bad pressure switch.

 

You gave the circuit power by jumping the relay. Bad relay... If you have power when you complete the circuit with your a/c switch your relay is good. If you have this power and your compressor is engaging and releasing you have a pressure problem. If you have a complete circuit and proper pressure and you still have engagement problems you have either a worn compressor clutch or a bad pressure switch. Check the pressure switch connector with a jumper. Check the gap on the compressor clutch.

 

For some reason those little black ants love relays. You can take the relay out and pop the cover off to see what's going on inside. Those ants can prevent the points from making contact and thus the relay does not work. Save some money check for ants first.

 

It COULD BE a bad relay but If the 30/87 contacts are the relay contacts you only proved the clutch works.

Pull the conn off the accumulator and jumper it. Does it work now? That means the cycling switch sees low pressure {is bad}. dont leave jumpered, though.

Now look for HP switch on the liquid line. Jumper it. TEMPORARILY. It opens when it sees too high pressure.

I'm reading off the ALLDATA diagrams for 99 Brava.. yours may vary.

 

To test the relay, just swap it! All the relays the same shape are identical.

 

Relay is good. Tried jumping the connector for the low pressure switch, and boom, the A/c kicked right on. I will try to replace the switch today and see if that does it.

 

What is the system pressure? It must be maintained above ~25psi or the low pressure cutoff will disable the compressor clutch.

 

Replaced the low pressure switch, and boom! the compressor stays on like it should.

However, the A/C isnt very cold. The pressure on the low pressure port when running is 55 psi, and it is 90* outside.

 

You could also have a problem with the blend door actuator. Will it change to hot properly or does the temperature just stay about the same all the time?