Toyota Repair: AC toyota 4 runner, r 134 freon, r 12 freon

Question
QUESTION: i have an 1989 toyota 4 runner 22r motor.The A.C compressor will not come on.When i press the A.c switch the button light will not come on.Where is the pressure switch for the compressor and does the A.C button switch not lighting up mean that it is bad.I am sure it is low or out of freon

ANSWER: The first thing that has to be checked is the freon pressure, if there is not enough or no freon the compressor will not turn on and the light on the dash will not turn on, the R-12 freon is no longer available so you should consider changing it over to the later R-134 freon, the retrofit kit complete with instructions and freon is available at most auroparts stores and can be be done DIY, just follow the instructions then see what happens, if there is a leak then the freon will leak out again in a matter of time and the leak will have to be located and repaired.

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QUESTION: The truck has been changed to the r-134.But I need to find the pressure switch to get the compressor to come on ,and take the freon.The freon is to low so the compressor will not come on to take the freon to charge it.I am just tring to get the system to take the freon and go from their.Any advice you can give me will be greatly appreciated.I just want to say think you for taking time out of your life ,to help people like me that can't afford to carry stuff to the shop. thanks          matt

Answer
The compressor will come on as soon as it gets pressure from the freon source, the pressure switch is seldom the cause, it's located inside the evaporator housing which would have to be removed and disassembled to get to the switch. You can force the compressor to run by disconnecting the electrical connector to the cluth and then applying battery voltage directly to the clutch connector.