this is a video by rich pin today we're working on a saturn s-series but this procedure we're going to be doing today can pertain to any vehicle and what we're going to be doing today is checking the AC pressure of the air conditioning system now what you'll need is a manifold gauge set now make sure before you start that the valves are in the closed position the high and the low make sure they're both closed then take the gauge set and put it right up here on the hood this is a good place to hang it then we need to find the service port they're all in different places on different vehicles now on this particular car you can see them they're right here with the red and the blue cap the red cap is the high port the blue is the low point now they're different diameter ports so you cannot cross the lines putting the rhein lines on the long way okay now we can take the cap here off the low ports and now a good idea is to good practice is to use your safety glasses when you're dealing with refrigerants like this there's the small port hi boys now the next thing we want to do is go inside the vehicle and take a thermometer place it in the center vent because you want to measure the output of the air and what we're looking for us where we'd like to get it around 45 degrees so concentrate on trying to see if your temperature can get down into the 40 degree range that would be that would be good know what we're going to do is start up the vehicle turn the fan on to the third position that seems to be the most efficient not high and then we'll put the recycling button on for max air and then turn it on now before you can check the pressure of the system you need to bring the engine idle up to 2,000 rpm now in this vehicle I'm going to be using a piece of credit card underneath the throttle stop that will bring it up the right rpm now we can check our preference and of course you want the engine be warm also too busy precious Jeff now the low sides and the high side pressures are low that usually indicates a low charge now if the low side pressure is low in the high side pressure is high that usually indicates a blockage in the system the expansion valve now if the low side pressure is high and the high side pressure is low and then if the needles are vibrating that indicates usually a faulty reed valves in the compressor if you're low size and your high side pressures are high that usually indicates that the system is overcharged now here is a temperature pressure shot that will help you determine what your pressure should be for what the ambient temperature will be and that's all there is to checking your pressure in your AC system
