I have a 83 mustang conv with a 5.0, i'm having trouble with the A/C. I started out with a leak and replaced the o-rings and recharged the system and still did not work. So i just ran a 12 gauge wire to the battery and to the positive side of compressor and it cools good. So that eliminates the clutch. I did a voltage check and there is no voltage. So i traced the wire to a relay that was under the dash, and i made a jumper to check the relay, and again it work. I go and purchase a new relay and i think i have it fixed and it does the same thing. Can any body help me with this?

 

how about the selector switch for the a/c? is that in working condition? that would be the next step.

 

the selector works fine also. as long as i have the relay jumped everything works perfect. It has been ten years since i have worked on a mustang, so im kinda rusty where everything is located. i'm wondering if maybe it might be a bad low pressure freon sensor. or another relay that controls that relay.

 

it could be either the low or high pressure switches keeping it from coming on, get your self a set of gauges and see what the pressures are at