Help! A/C compressor not turning off.

[fordby4]

The other day I notice that the a/c compressor is not shutting off. Even when the button that controls the fan speed is not pushed. The air is cold and works fine its just that the compressor is constatnly on and hurting my gas mileage and performance. Also now I noticed that the clicking noise it used to make ,after the button was pressed to start cycling the compressor, comes on when the fuel pump is engaged before initial start up( when the key is in the ignition). So maybe it is an electrical problem but I am not sure. Any help will be appreciated.

 

[biggs92EB]

The other day I notice that the a/c compressor is not shutting off. Even when the button that controls the fan speed is not pushed. The air is cold and works fine its just that the compressor is constatnly on and hurting my gas mileage and performance. Also now I noticed that the clicking noise it used to make ,after the button was pressed to start cycling the compressor, comes on when the fuel pump is engaged before initial start up( when the key is in the ignition). So maybe it is an electrical problem but I am not sure. Any help will be appreciated.

well its a pain, but you could always unplug it at the compressor, your a/c relay is probably faulty. Another thing when the button is pressed in and the fan is off my a/c pump still runs, and when its on defrost too if i remember right....

 

[shamaal]

A number of possibilities. The compressor clutch is electrically engaged, the power comes from the A/C clutch switch on the accumulator. When the pressure is high enough it comes on. When the pressure is low it turns off.

1. The switch may be bad. Unplug the switch at the accumulator and run the car again. If it is still engaged the clutch is bad, it happens occasionally.

2. If the clutch is no longer engaged, the switch is a good failure candidate. It unscrews from a schrader valve on the accumulator. A schrader valve is like the valve on your tires it should be self sealing. Wear eye protection, there's been a least one instance of a leaky A/C schader valve.

3. The correct troubleshooting procedure would be to hook up a set of gauges and read the pressures. If <25 psi and clutch is engaged, the switch is bad or clutch is bad. If > 44 psi and not dropping and the pressure isn't dropping, there may be an obstruction in the system.

It is true that the more sophisticated systems energize the A/C compressor in defrost, the early models were not sophisticated.

You can read up on A/C systems in the A/C subforum

 

[fordby4]

I pulled the fuse for the ac clutch under the steering wheel and that stopped the clutch from engaging. So would that be the clutch cycling switch that is bad? Also I went to go remove the switch and the freon started coming out. I figured since it was on a valve it might let a little out but I didnt try it. Once it started coming out I quickly retightened it. Is that normal or should there be no freon loss. Thanks for all the info.

 

[shamaal]

The switch is screwed into a schrader valve, like on a car tire. Occasionally they get stuck, that sounds like what happened here, see #2 in my previous post.

Options:

1. Connect gauges, replace switch, accumulator and orifice tube, evacuate system and recharge with refrigerant.
2. Buy new switch and rapidly swap. Add a new can of refrigerant and hope for best.
3. Find a friendly A/C shop, bring them switch and have them replace.

Good Luck

 

[Blacksheep Josh]

if you want the system to not work, do what i do.

during the winter, i change the belt system. there was an engine w/ a/c, and an option without (rangers)

it has a sticker in the engine bay for which belt you want, but i take the belt off, pull the fuse, close up everything, and unplug it