If you look on the low pressure side of the AC system you will see a plug that is incorporated in to the line. It will have two wires leading to it. Remove the plastic clip that attaches the two wires to the sensor and use a short piece of wire to connect the two terminals in side the plug by putting the ends into the cap. This will bypass the low pressure sensor and allow the AC clutch to engage and begin to cycle again. Remember this low pressure switch is there for a reason. If you don't add more r-134 to the system and allow the AC compressor to cycle you will destroy the compressor. You need to charge the system when you bypass the low pressure switch and get the system up to full charge status and reconnect the switch.
Look for the accumulator(silver can a/c lines go to) on the passenger side of engine area. The Low side charging port cap should be on the side of the accumulator.
Basic AC system consists of Compressor pump (on engine), Condenser (front grill with radiator) and Evaporator (Firewall). Pump has two ports output (high pressure) and return (low pressure). Follow lines from pump. High side is usually between pump and condenser. Follow lines and find second port this will be low side (refill) port. Paint or replace port caps (red high, blue low). Also, refrigerant in system determines port size (R12 or R34).
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I don't know what testing you have done? Any applicable hvac trouble codes? Note the diagram, is the compressor clutch energized? In the diagram, top wire for compressor clutch is voltage. The bottom wire is ground. Check voltage and ground with everything turned on, use a test lite. There are fuses involved, also. Could be problem with pressure switch?
Replace the instrument cluster . GM had stepper motor issues 2003 to 2006 . Pin out won't help you , The info for the instrument cluster gauges come's over class 2 serial data buss (network) from the PCM - engine computer . Do you know what GM class 2 data network is ? All gauge info comes over one wire from the PCM . How to repair GM Instrument Cluster Speedometer Gauge Stepper Buick Class 2 Operation Diagnosis 1998
Hooking up a Tech 2 scan tool an checking for code's an data to the instrument cluster would be the correct diagnostic procedure . But you wouldn't know that , not being a Chevy technician . Not having factory service repair info. manual .
Speedometer
The IPC displays the vehicle speed based on the information from the PCM. The PCM calculates the vehicle speed from the vehicle speed sensor (VSS) circuit. The IPC receives a class 2 message from the PCM indicating the vehicle speed. The PCM also calculates the vehicle speed based on the wheel reference vehicle speed class 2 message from the EBCM. The PCM uses the vehicle speed information from the EBCM as a backup. The IPC displays the vehicle speed information from the EBCM when the PCM detects a malfunction in the vehicle speed sensor circuit.
The speedometer defaults to 0 km/h (0 mph) if the IPC detects a loss of class 2 communications with both the PCM and the EBCM.
Engine Coolant Temperature (ECT) Gage
The IPC displays the engine coolant temperature on the analog ECT gage as determined by the PCM. The PCM monitors the signal circuit of the engine coolant temperature sensor. The IPC receives a class 2 message from the PCM indicating the engine coolant temperature. The IPC illuminates the check gages indicator when a high engine coolant temperature condition exists. The engine coolant temperature gage defaults to 75°C (160°F) or below when one of the following conditions occur:
• The PCM detects a malfunction in the engine coolant temperature sensor signal circuit.
• The IPC detects a loss of class 2 communication with the PCM.
For additional informatin on the engine cooling system, refer to Cooling System Description and Operation in Engine Cooling.
Engine Oil Pressure (EOP) Gage
The IPC displays the engine oil pressure on the analog EOP gage as determined by the PCM. The PCM monitors the signal circuit of the engine oil pressure sensor. When the engine oil pressure sensor resistance is high, the engine oil pressure is high. When the engine oil pressure sensor resistance is low, the engine oil pressure is low. The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The IPC illuminates the check gages indicator when a low oil pressure condition exists. The engine oil pressure gage defaults to 0 kPa (0 psi) when the following condition occurs:
• The PCM detects a malfunction in the engine oil pressure sensor signal circuit.
• The IPC detects a loss of class 2 communication with the PCM.
Fuel Gage
The IPC displays the fuel level on the analog fuel gage as determined by the PCM. The PCM monitors the signal circuit of the fuel level sensor. When the fuel level sensor resistance is high, the fuel gage indicates full. When the fuel level sensor resistance is low, the fuel gage indicates empty. The IPC receives a class 2 message from the PCM indicating the filtered fuel level percent. The PCM uses 2 filters for the fuel level percent. The slow filter is used during normal operation. The fast filter is used when the engine is just started or when the vehicle is in Park or Neutral. The fast filter allows the fuel gage to reach the current fuel level quickly. The fuel gage defaults to empty when the following conditions occur:
• The PCM detects a malfunction in the fuel level sensor circuit. Refer to Diagnostic System Check - Instrument Cluster .
• The IPC detects a loss of class 2 communications with the PCM.
Reviewing the fuel system description will further explain how the system functions. Refer to:
• Fuel System Description in Engine Controls - 4.3L
• Fuel System Description in Engine Controls - 4.8L, 5.3L, and 6.0L.
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the gas from the compressor is pumped to the condenser to be turned back to liquid to go to the TX valve to be released and be turned back to gas
if the condenser is blocked , the gas is turned into liquid by the high pressure generated by the compressor in that line
from the condenser on there will be low pressure as the compressor forms a vacuum back to the condenser
the low side is the hose from the evaporator to the compressor
the high side id the hose from the compressor to the condenser
The guage needs to read between 35/40 psi.. If its much higher you may be overfull, this causes it to not cool.. Fix by letting some freon out, then top it back to needed pressure.. If pressure is correct, it would be a clog in the system.. Usually an orafice tube or accumulator..good luck!
LOCATE THE LOW PRESSURE LINE AND FOLLOW IT, THEY ARE GENERALLY NEAR THE FIREWALL AREA, IF THAT DOESNT WORK, TRY A STANDARD HELMS REPAIR MANUAL, AS IT SHOULD BE LISTED THERE. WORST CASE SENERIO, JUST CALL THE DEALERS SEVICE DEPT. AND THEY SHOULD TELL U WHERE ITS LOCATED AT, AS IT HAS WORKED FOR ME IN THRE PAST.
Could be either. Usually if the compressor is cycling than its usually low on refrigerant. Could be pressure sensor. Could be cooling fan. I would have a different tech look at it. It is hard to diagnose what is going on without knowing pressures of the high and low side from a gage hooked up to the system.
YOU NEED A R-134 GAUGE SET TO CHECK LOW PRESSURE SIDE AND HIGH PRESSURE SIDE.YOU ALSO CAN BUY A LITTLE CHEAPER GAUGE TO CHECK YOUR AC LOW BLUE SIDE AND HIGH RED SIDE AT ANY AUTO ZONE OR ADVANCE AUTO PARTS.WHAT YOU DO WHEN YOU GET YOUR GAUGE SET HOOK GAUGE TO LOW PRESSURE SIDE BLUE CAP PORT AND GAUGE TO HIGH SIDE PRESSURE RED CAP PORT.YOU CRANK CAR UP GET IT OPERATING TEMPERATURE.THEN TURN AC ON HIGH COOL LET RUN 3 TO 4 MINUTES.CHECK LOW SIDE GAUGE READING SHOULD BE 28 - 32 PSI. HIGH PRESSURE SIDE GAUGE SHOULD 199 - 228 PSI. THATS NORMAL CHARGE. SEE YOU CANT JUST RECHARGE AC SYSTEM UNTIL YOU CHECK IT FIRST YOU WILL DAMAGE SYSTEM .NOW YOU CAN GO TO AUTO ZONE PARTS BUY A CHARGE CAN WITH GAUGE AND HOSE.ATTACH TO IT.YOU NEED MORE THAN ONE CAN.WARNING MAKE COMPRESSOR IS RUNNING WHEN YOU TURN ON AC .BECAUSE IF COMPRESSOR NOT RUNNING CHECK FUSE AND AC COMPRESSOR RELAY.IF BOTH OKAY.YOU COULD HAVE OPEN CLUTCH COIL A FAULTY LOW PRESSURE SWITCH WILL CAUSE AC NOT TO WORK. IF LOW PRESSURE GAUGE BLUE SIDE PRESSURE IS 28 OR 30 YOU DONT NEED A CHARGE.PROBLEM SOME WHERE ELSE.BE SURE TO WEAR SAFETY GLASSES WHEN WORKING ON AC SYSTEM.
When this happens, my first suspicion is that the system needs charging. If you don't have a gage to check the low side pressure, you can bypass the low pressure switch by removing the connector and placing a paper clip across the terminals in the connector. If this allows the clutch to engage, charge the system. If not, then read the diagram at the link to see other possible causes, such as the fuse, the relay, or the control panel. http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=136025
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