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Old 06-03-2002, 07:01 PM
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The trinary switch senses head pressure and when it typically gets to 270psi (+ or- 15lbs) it will turn on your fans. If you have been running the car on the road at any speed at all, the forced air will cool off your condenser and keep the head pressure down. If you are idling at a dead stop for any length of time, your headpressure will come up and your fans should come on. Your A/C will work much better if you manually turn on your fans when you are in heavy traffic rather than wait for the trinary to turn them on. If you suspect that you are low on refrigerant, check your reciever-drier for a sight glass. If it has one, look for bubbles. A r134a system should have just a few bubbles now and then. A r12 system should be clear. A good indicator of leaks is a slight oil film near fittings or near the front of the compressor. Your a/c system has oil suspended in the refrigerant and if there is a leak, it will generally leave a film of oil in that area.
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