2004 Envoy - Do I need to drain the refrigerant from my A/C system to replace the high pressure transducer or does it have a schrader valve?

To check fuel pressure on a 2005 Magnum 5.7L, you will need a fuel pressure gauge and some basic tools. Here are the steps to follow:

1. Locate the fuel rail on the engine. This is a metal pipe that runs along the top of the engine and has fuel injectors connected to it.
2. Remove the protective cap from the Schrader valve on the fuel rail. The Schrader valve looks like a tire valve and is used to measure the fuel pressure.
3. Connect the fuel pressure gauge to the Schrader valve. Make sure the gauge is securely attached.
4. Turn the key to the "on" position but do not start the engine. This will prime the fuel system and allow you to measure the fuel pressure.
5. Read the fuel pressure gauge. The fuel pressure should be between 58 and 62 psi (pounds per square inch) for this engine. If the pressure is too low or too high, there may be a problem with the fuel pump, fuel filter, or fuel pressure regulator.
6. Turn off the engine and disconnect the fuel pressure gauge. Replace the protective cap on the Schrader valve.

It's important to note that working with fuel can be dangerous, and it's important to take the necessary safety precautions when performing any work on your vehicle's fuel system. If you're not comfortable performing this task, it's best to seek the help of a qualified mechanic.

Evacuate the system and replace the valve core. Then pull a vacuum and recharge with refrigerant and whatever oil was lost.

R12.... In 1994 R134a was required, but some changed earlier. Yours may have been converted. If the service ports are threaded it still has R12. Hope this helps.

Look at the lines (aluminum) and the size of the lines. The low pressure line is the bigger of the two where as the smaller line is the high pressure side. Normally the low pressure Schrader Valve is nearer the radiator just up from the canister dryer.

You will add R134a refrigerant to the low pressure side. There willl be to schrader valves, one for the high, and low pressure sides. You can only charge the low side. To locate the inlet, you will follow the lines off of the a/c if you are not sure where they are, it will have a cap over the schrader valve that reads L, that is the one that you charge.

yes with a schrader valve removal tool but before you do that check for dirt in the openning of the valve and if no dirt try to tighten schrader valve hope this helps

It doesn't take much pressure for fuel to come at schradrer valve.You need to know if there is enough fuel pressure to open poppets inside of the intake 40-50psi has to be at the schrader valve to unseat the ball on the end of the poppet,Are you getting spark?

On this Chrysler product they have an A/C Transducer located on the high pressure hose. The switch has three wires. They also have a thermo sensor located at the evaporator case behind the glove compartment. These two things are the only ones thatA jump in the system is only removing protection the system has. So it will damage your compressor or hoses. Find the compressor follow the high hose to the high pressure switch (transducer) it has three wires. Check under the dash by the glove box and you will see a round platick lid on the case with two wires that is your thermostat (thermo sensor).
control the compressor.

The A/C clutch is controlled by the A/C cycling switch (19E561) and the A/C pressure cut-off switch, which are connected in series. The A/C cycling switch is mounted on the suction accumulator/drier (19C836), and the A/C pressure cut-off switch is mounted in the discharge line at the A/C condenser.

The A/C cycling switch closes when the pressure on the low side of the system reaches approximately 276-324 kPa (40-47 psi). The A/C cycling switch opens when the pressure drops to approximately 163-175 kPa (23.5-25.5 psi), disengaging the A/C clutch. In ambient temperatures below -1° C (30° F), the A/C cycling switch will not allow compressor operation because of low system pressures.

The A/C pressure cut-off switch is used to interrupt A/C clutch operation in the event of high system discharge pressures. The A/C pressure cut-off switch is a single-function switch that controls A/C clutch engagement. When compressor head pressures rise to approximately 2896 kPa (420 psi), the contacts open, disengaging the A/C clutch. When the pressures drop to approximately 1724 kPa (250 psi), the contacts close to allow A/C clutch operation.

This problem can be caused by low refrigerant charge. Check with a manifold gauge set and temperature pressure chart.
The cycling switch is replaceable and there is a Schrader valve on the accumulator port so you do not lose your system charge when replacing. It screws on/off. It is available at any auto parts store. It protects the compressor from low pressure which can be caused by a loss of refrigerant and subsequent lack of lubrication and prevents evaporator freeze up. Replace the switch. It is about $10. The high presure switch is about $25.

if you open up the hood and find your fuel rail you should see a little cap just like what is on your tire valve stems. take the cap off and push the little valve in the center agian just like the valve stem on your tire. be vary carefull as fuel will spray out of this. that is how to depressurize the fuel system