Suburban hwt gas won't light/deliver.

[Glenlivet]

Hi, apologies if I have started a new thread on a boring known issue, but I couldn't find it discussed.
It's a new to me 5th wheel with Suburban hot water tank and I can't get it lit.
There is gas present, right to the 90 brass elbow behind the water tank door. The stove/fridge/furnace work properly. The propane system has been closed, gas released, turned back on very slowly and purged.
Electric water heater is off (no 110 feed to the trailer)
Tank is full of cold water, HW gas switch is on, and system is pump pressurized.
When the trailer's main 12 volt disconnect is reset to on, the water tank's peizo electric lighter snaps healthy sparks for the expected 3 times in its attempt to light the burner but obviously no gas is being delivered.
When the peizo is snapping, the gas valve solenoid in the water tank compartment clicks and can be felt by finger to be doing something.
While the lighting attempt is happening there is a measured 10 volts between ground and the double solenoid that allows gas to flow, for the time that the lighter clicks. This is with 12.8 volts available at the batteries.
Sooo...
Is the solenoid valve faulty?
Is 10 volts too little to properly open the valve? Is this likely to be a control board issue? And of course has this happened to anyone?
Thanks for any help anyone has.

[Glenlivet]

Edit: Houston, we have a problem.
I should have checked those parallel wired gas valve solenoids unplugged, and out of circuit and individually. As it happens the full 12+ volts is there and the outermost one is open circuit, no matter how diligently I sand and clean the unplugged terminal spades. I think I have my answer. Thanks all for your time.