While looking for my treadle valves, I found my air horn solenoid

[Steve P]

There is one of these in my drivers side run bay (directly under the driver).  Air lines and electrical connections.  Thank goodness an internet search answered the "What is this?" question.  But for others, I post this helpful hint with pic.  It's mounted 90 degrees counterclockwise from the way the pic appears.  The search fore the treadle valves continues... I wish I knew what they were supposed to look like.  I'm searching the genny compartment (and the internet).