It was blowin hot air

I have a 98 mustang and the cluth on the a/c compressor want engage unless it is hotwired. Would someone kindly direct me as to what to do? Also I am having trouble finding the a/c compressor cluth relay. Any help would greatly appreciated.

Most likely cause is low refrigerant pressure. You need a gauge to test this.

Does the system get good and cold if you do hotwire it?


yes,it blows cold air when hotwired,and i am afraid to drive it hotwired being that it may cause more damage.would it be okay to drive the car hotwired untill i can find out what the problem is? Most importantly thank you for taking the time to address my problem. also i still cant locate the clutch relay,and would greatly appreciate any help in finding it.Thanks

I wouldn’t drive it with a “hotwired” compressor. If the compressor clutch is thus permanently engaged, it’s possible you could damage something in the A/C system, possibly by freezing up something. Also, the engine would be hard to start with the drag of the compressor, you would not get good acceleration as the compressor won’t be cut out under heavy engine load, and the A/C will freeze you out of the car if it can’t cycle.

You’re just going to have to follow the wires from the compressor (and clutch) to wherever they lead.

First off I want to point out that the A/C compressor clutch circuit is only engaged with the key in RUN. When you turn it to start, the clutch disengages. Unless you’re drawing power from the fuel, ignition or starting system to run the compressor, it turns off.

I’d like to know how exactly you’ve hotwired the compressor. Did you bypass the low switch? Jump the relay? How’d you do this.

I ran an A/C system “hotwired” for almost a year. Except I had a little switch in the car that I could turn the compressor on and off with. I finally decided to do the full repairs to the A/C electrical system when the switch I was using got fused in the on position and I couldn’t turn the A/C off. A regular old hotwire should be fine but if you ever experience a loss of cooling I’d suggest pulling over and pulling the plug immediately.

What you really need to do is find out why the A/C compressor isn’t coming on. Whatever you bypassed to hotwire it may have a problem. Again, knowing HOW you hotwired it will help in figuring out what’s wrong and what needs to be done.

The last thing I would suggest is that you go buy a gauge from one of the auto parts stores. They’re not too expensive. You only need the low side gauge. Put it on and run the engine at 2000 rpm for five minutes with the A/C set to max and the windows wide open. If the gauge pressure drops below 15psi, you’ve got a problem. Post back with whatever pressure it reads. After that, repeat the same test but this time spray a little water onto the condenser (in front of the radiator) and oberve the pressure. Post that one too.