I'm pleased to say that your help has paid off. I confirmed the voltage is switching at the pump connector, but the pump only repsonds intermittently. I think it's a gad diode on the PCA, but no worry, just going to get a new pump.

I still have a question though. I believe I have a leak in the pass. front door based on the hand pump leak down tests from the main line in the trunk and the hissing from the pass. front door. However, I took the pass front seat out and felt all around under the carpet but couldn't find that manifold. I did find what I believe is that yellow main line going under the pass front seat and under the center console. Could this manifold be under the console, or under the driver's front seat? I'd like to see if I have any other leaks while I'm fixing them.

Frank.

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'82 300SD