1999 E300D turbo diesel

Trying to get my AC working and the on-board diagnostic codes indicate I'm low on refrigerant. I have a DIY fill kit and I want to ad refrigerant myself.

I think I've located the low pressure gauge/fill fitting... but not sure... since it doesn't have blue color cap on it ?? It's in the engine bay on the drivers side fender well behind the windshield washer reservoir... Is this correct??

Where is the high side fitting....just in case I get hold of a set of proper gauges.

Does the on board diagnostics (code #7) read low side or high side pressure.

What should it read to be in spec?

Warren C.

#7 reads the pressure at the dryer outlet. If there is no restriction, that's the high-side pressure. You should get a proper set of gauges, as otherwise you have no idea if there is a restriction and thus very high head pressure.

The high-side service port is located on the condenser, upper left corner. After removing the internal grille insert, there is a small plastic piece in the auxiliary fan shroud covering the auxiliary fan power connector and the service port.