[rustybuick]

What causes this? It's a 92 2.3L. Thanks for any help.

[heavy metal]

do you mean the a/c compressor cycles with a/c off?...it will cycle with the defroster on.

[74stang2togo]

Ford has done this for years to keep the A/C compressor working longer.

If the compressor didn't cycle for long periods of time (fall, winter, spring) the seals would deteriorate and cause it to leak and the lubrication in the system would puddle at it's lowest point, resulting in a dry startup for the compressor at it's next use. The solution Ford came up with (and other manufacturers as well) was to make the compressor cycle occaisionally when the heater or defroster were on. My 1975 Thunderbird did it, and my '76 Mustang II does now, so I know it's been around for at least 30 years, it's not noticeable on most of them, but on 4-cylinder cars it's pretty obvious because the A/C compressor takes up about 20% of the total power output of those engines!!!

[fox81]

Indeed it does. Thats why I hardly ever run my A/C unless its down hill. lol. But there are exceptions when it hits 105+ here in sunny Tucson Az.

[rustybuick]

I always get the best info here. it's weird, I remember sitting in the back of a Crown Vic cruiser years ago waiting for the officer to decide my fate....I always remember the sound engine RPM's at idle raising and lowering as some relay clicked over. Now I know what it was.