did you disconnect the solar , coach battery positive and shore power
if NOT it can confuse the multi meter readings by feeding voltage back to the solenoid
measure the voltage at the
disconnected coach battery CABLE to a ground
CONFIRM it read 0v (zero)
on the solenoid .......
one of the BIG post should always be live.... 12v this will be chassis battery
the other should be 0v the feed to coach battery.
have someone jump the two BIG posts on the solenoid with a screw driver
or attach a temporary wire across the posts
measure the voltage again
at the disconnected coach battery cable to a ground
it should NOW read 12v while the jumper is connected
IF it does.... you have confirmed you are working with the correct solenoid
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to check if solenoid works .
put a jumper wire from the post that connects to
chassis battery 12v to the bolt holding the black wire with blue terminal at end..
you should hear or feel a click
measure the voltage on the solenoid post that goes to coach battery should read 12v while you hold that jumper to the black wire with blue terminal
if you hear NO click or not getting 12v on the coach post..
check the ground / negative wire to the solenoid bracket..
Very hard still to see the posts and where the red wires are going...
It looks weird to me almost as if the solenoid has been bypassed
better picture required!