I have a 3rd generation 3.0. The suction port is up near the firewall, under the wiper tray. The high pressure line is on the passenger side, inside fender. The low side (charge port) should have a blue cap on it and the high side, a red cap. You can't interchange the R134 hoses because the fittings are a different size.
Note that your 3rd gen van no longer uses the conventional mechanical low pressure switch. So don't jumper anything to start the compressor except the mechanical compressor relay in the PDC. All pressures (both high and low) are sensed by a pressure transducer that sends a signal to the ECU. The transducer works with the ECU in a very tight voltage range (tenths of a volt).
EDIT: I just happen to have a picture. I see that the OEM caps are actually black. The hose in the picture is going to the charge port (suction) and the high side port is visible, but hard to pick out. It is above the frame rail on the left. See the 2nd picture below. Note that in this picture the alternator is off. I had to replace the high side line and the leaking high side port. In the 2nd picture, you can almost pick out the refrigerant oil on the cap and you can see where I wiped it off the frame rail.
