[coolwhip]

Update on the boost gauge installation problem.  After learning that the gauges for my 2018 Venice were manufactured by Speedhut, I contacted them for info on the boost gauge, and was directed to Dave at Open Road Moto Sports in St. George, UT.  He went the extra mile to help me, and after numerous emails and photos we finally determined the gauge was probably faulty.  I got another one, installed it as per the obvious plug-in connections, and it worked.  If my dealer would have been willing to work with me, I could have solved this right away, without wasting time trying to get factory help, or help from several other dealers around the country who were no help.
I'm impressed by Dave at openroadmotosports.com.
I'll post installation instructions under "Tutorials & DIY" below.