Honda Ridgeline Owner's Manual page 228

Towing a Trailer
To disconnect the connectors,
reverse the connection steps, then
make sure the socket lid and
socket cover are securely in place.
Avoid using excessive force when
disconnecting the connectors.
222
Important Precautions
Before you submerge the trailer
hitch in water (such as at a boat
ramp), make sure the connectors
are removed and the socket lid
and socket cover are securely in
place. Failure to do this will result
in electrical system problems.
After the connectors are
submerged in water, open the
socket lid and the socket cover to
drain them.
Electric current flows through the
electrical supply circuit only when
the ignition switch is in the ON
(II) position.
Using the electrical supply circuit
when the engine is at a stop or
idling can discharge the battery.