A/C low pressure fitting

[CharlieM]

I have a 2001 Gas Mountainaire with the Workhorse/8.1L setup. My dash A/C is blowing tepid air and I suspect it is just low on R-134. Where is the low pressure fitting on this rig. I looked under the hood and couldn't find the normal "Blue" cap that marks the low pressure side of the A/C. I am familiar with recharging the systems as I do it for six vehicles on an annual basis, I just can't seem to find the low pressure fitting on this one.

[CharlieM]

Found the low pressure fitting next to the air handler. Did the hot/cold check of the hoses and found the fitting under a BLACK cap. They are normally Blue. Serviced up the system and all is cool breezes now.

["007"]

Charlie, if you still have a problem with warm air coming from your dash vents some of us have added a ball-valve in hot water line entering the Evans control valve to shut off hot water entering the heater in summer months thus aiding the AC portion to cool up front easier.