[coolwhip]

I purchased a Boost Gauge for my 2018 Venice at my dealer with the intent of installing myself.  It came without directions or the wiring harness that is advertised as being included. My dealer, Lynnwood, would not help.  For no price would they show me where to plug it in.  They would only install it themselves with an open-ended credit card.  Suggested it would cost up to $400.  Two other dealers were helpful on the phone but following their directions (plugging into the two gauge daisy chains - the obvious way to install) it did not work, and caused my other gauges to be erratic, and gave me a check engine light. None of the dealers seem to be sure if there is really a different harness needed.  The factory won't answer emails on technical issues.  I now have a $200 paper weight.

Does anyone have any suggestions?