If I leave the 120 volt air pump on during the night I have air to flush the toilets. If I shut off the 120 volt air pump & turn on the 12 volt air pump I run out of air & the toilets won't flush. The gauge on the 12 volt air pump shows air pressure. Is the 12 volt air pump not plumbed into the toilets?
Hate to answer my own question, but it may help some one else. I spoke with Tuga who answered some questions and gave me a direction. The thing that threw me was that the 12 volt air pump gauge showed pressure so I assumed it was working. Unknown to me was that the 120 volt air pump fills both air pump tanks, although the 12 volt pump only fills its own air tank. So I turned off the 120 volt air pump, drained both air tanks & turned on the 12 volt pump--nothing. I checked for 12 volts at the pressure switch & had nothing. Went to the fuse box & found a burnt fuse. Replaced fuse & tested for 12 volts at pressure switch & it was hot. Tested pump & it works. We'll see if the fuse blows with use. Thanks Tuga for your ear!