Well it sounds like you have done quite a bit of work to avoid recirculating radiator discharge air. That is good. One thing that comes to mind is the cowl vents. I chased a similar problem on an early A body mopar when I lived in northern Colorado. The heater would work ok until I cleared 20 mph. T...

Ok, the series condenser should work - we have discussed this one at length on the old board. But let's get the basics out of the way. Is the engine the original Pontiac 389? A later 455? An LS swap? Are the engine & water pump pulleys OEM? Aftermarket? Swap to later serpentine? Is the fan in a ...

You need to take it someplace & have it recovered. See how much charge is in it. You need to find a wiring diagram, and find out why it allows the low side to run in vacuum. You need to pull the expansion device out & find out WHY it is blocked. Nothing appears to be wrong with the compresso...

I just re-read your posts. A test with new gauges gave the same pressure on both sides, I should have caught that. But your last post says: if you shut the high side gauge down as if your going to charge it the low side pressure drops to zero. High side does not change. Also notice that when I disco...

Is the new condenser the same as the old unit? A 1997 would have had a serpentine condenser about 1.250 thick. I have seen replacement condensers that are parallel flow units about .75 thick - just like the 2002 & up units. The parallel flow condenser is a good one, but it holds less refrigerant...

Does the evaporator have a TXV? The compressor may not be bad. Which model Sanden is it? I would probably recover the system to see how much chage remains, and inspect the expansion device. I would also open the suction line at the compressor. You want to see a little oil film in the suction line at...

When I see a POA system with 29psi low & 155 psi high, all I see is an evaporator with no airflow. Is the suction side cold? Do you have a low side port on the compressor side of the POA? Not all systems have this, but some do. If you raise the engine RPM to 1500+ does the evaporator stay at 29p...

Pushers are always a handful with A/C. Is this the dash A/C you are working on? The long lines & odd configurations that are manufacturer specific can lead to some odd pressure readings. Are the service ports both back at the compressor? Sometimes you will find a low side port near the evaporato...

Because a diode tested by itself will give a resistance higher than the coil in either direction on your DMM, you need to apply a small load to cause current to flow through the diode. The resistor is used to build a voltage divider. With the coil & diode assembly connected as one of the two res...

The 1999 Safari is built on the GM P32 or Workhorse chassis. HT6 compressor.

Coach builders did all sorts of things with the dash A/C If they used mostly the GM P series parts it has an orifice tube.

Which engine is in this unit?