Gary, the dump valves seem to work better plugged in to shore power, or with motor running. The higher voltage makes them more "lively". If your batteries are marginal, 12.0-12.2 volts, they seem to really struggle to open and close. You may also have bad switches. Check to see if you have continuity thru the switches. If not, switch needs to be replaced. The one that is leaking needs to be replaced eventually. If it were me, I would replace both at the same time because of the difficulty to access them. Hope this helps.