89 E350 Jamboree Rallye AC charge port location

On my 1991 Tioga E-350 the low pressure port is located out of site up under the cowling. Ten years after having it converted to R-134a it stopped cooling. After locating the low side port with a mirror I was able to connect the low pressure hose from the charging kit by feel without having to remove any panels. I cut off the charge when the low pressure gage reading was witihin spec, and the recharge has lasted 3 years so far.