Just under the slide out, under the skirt you will find both grey and black valves. They are both marked on the skirt. Checkout the Vantage section under the community/social/vantage on this forum. You will find about 50 Vantage owners that have posted lots of good Vantage info including how some of us made cutouts in the skirt to make these valve more accessible. Good luck with your Vantage--we love our 32FLS.
Fran & Carol--Empty Nesters
2012 Keystone Vantage 32FLS
2012 Toyota Tundra DC 4X4 5.7 With tow pkg