not sure bout Jensen but Most are just a ground. some are on a timer, and like my clarions once you turn the unit off it likes to see a interupt in the ground. (toggle switch) or relay which ever you prefer.
it has to see a ground, non ground, then a ground.
I have the bypass code upstairs that works on pre 07 models tho //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif