I am having the same trouble with my 2016 Vegas. I am new to posting, but I see that no one has yet answered your question. I was trying to find the low pressure port this afternoon. If I have located the current port, it is just right of the high pressure port (If you are facing it) and tucked back and down a little bit. You will probably have to lift your air duct hose to be able to see it. It is very close to a rail. Mine has a clear cap on it instead of blue cap. So I am hoping it is truly the low pressure port. I will attempt to insert a picture of it.
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