I also have one doing the very same thing, if I hit the top of the dash real hard(like the old TVs) it will return to normal. It seems to happen more often when it's very hot out. I may pull my instrument cluster off to see if something is shorting out. It's a very intermittent and aggravating problem.
HVAC gauges should read the system's refrigerant pressure and temperature. The exact readings will vary based on the specific circumstances and type of system being used. It is important to refer to the manufacturer's guidelines or consult a professional for accurate interpretation of the readings.
Your high and low pressure readings will be directly affected by the ambient air temperature and humidity. At 60 degrees (Fahrenheit), you should be looking right about at 58 psig. At 100 (Fahrenheit), you'd be looking at something closer to 125 psig.
With AC pressure gauges and manifold assembly. This is best done by a professional.
jump a hot wire downt to it with it running with gauges on it and read the readings.
Gotta ask if there is fuel in the tank. Sometimes the fuel gauges give inaccurate readings.. Could also be a clogged fuel filter, bad fuel pump, engine timing, spark gap.
unfortunately the Chevy venture is known for have many of the sensors going bad. I have a 2000 Chevy Venture that gives the wrong readings for everything. I never know where my gas level is until it is actually 'empty'.
Your cluster is bad. Happened to mine.
Speedometer, fuel gauge, and temperature gauge.
Using a set of a/c gauges both the low and high side readings will be of equal value, meaning that the compressor has equalized or its very noisy.......
Sounds like a blown fuse to me. Last time my gauges went out, that was the cause. this just happened to me last week. It was the battery fuse under the hood, on the passenger side.
Happened to me while driving. Jumpstarts and waits only worked for a few miles. Was able to get to Sears and resolved problem with new battery. Also had them check the alternator.
Most oil pressure gauges operate by a varying voltage. The oil pressure changes the resistance in the oil sensor, causing the gauge to change readings.