I took my 93 4runner to a shop to have the a/c charged. They vacuumed the system down a it held a vacuum for a good while. They recharged the system and its seems to work fine. I was having a problem with the system before I took it in. When the a/c switch is pushed it lights up but doesn't urn on the compressor. There is a single wire coming of the compressor that activates the magnetic clutch. We can hook 12v directly to it and the system comes on and works fine. Not sure where to start looking to determine why the dash switch won't activate the compressor clutch.

 

There's a low pressure switch that won't allow the compressor to turn on if there is low freon in the system to protect the compressor from damage.

 

so which is it?

they recharged it and it works fine,
or the problem you had before they recharged it is still occuring?

you made both statements....

 

.......uhhh yeah. If the switch in the cab doesn't turn on the compressor, and the 'pressor comes on when directly hook to the power source, that usually means the in cab switch is bad. Just cuz the light on the switch comes on, doesn't mean the switch is working properly. Might be a broken or even dirty contact inside the switch. Replace the switch.....

 

Before you replace the switch, try adjusting the RPM dial on the amplifier. It's the small knob to the right of the rectangle on the front of the amplifier in the posted diagram.