A/C pressure?

[85VicWagonGuy]

1998 Deville gave "low a/c coolant" message recently. Now won't go from ECON to AUTO and stay there. Looks like time for a recharge.

But my cheesy gauge says 35psi in the system now.

What is the correct psi?

 

[85VicWagonGuy]

update

I added R-134A to bring the pressure to 45psi (max. safe pressure), compressor still won't turn on.

I also swapped the fuel pump and a/c compressor relays, in case the a/c relay was bad. Wrong again. Both relays are fine.

The display says that the A/C Pressure is Low.

Could I have a bad pressure sensor?

 

[85VicWagonGuy]

update 2

Decided to check my Crown Vic's a/c pressure... and the gauge showed that it had 45psi (like the Deville), but it dropped quickly to 25psi as soon as the compressor engaged. Soon after, the clutch would disengage because of low pressure.

Ergo... maybe my gauge is off and the Deville is still too low.

 

[85VicWagonGuy]

There seems to be plenty of 134a in there now.

Maybe the pressure sensor is dead.

135 viewers and no one has a clue about the correct pressure?