So guys I'm a little confused. Just ran across the site while sitting bored at work. Looks like a great site with some helpful people.
My question is about the Jensen VM9411 which I bought and installed last night. I got everything hooked up the way it's supposed to be...but not the way that I want it. I searched and read the posts about the grounding mod, but I don't understand. The wire is supposed to be wired into the parking brake switch, which I did and it works fine, but isn't this a positive source? It operates a light, right? So if I disconnect that and just ground it with a switch, how can the ground w/ switch send a "pulse" if there's no signal running through it? I'm not an electrician or anything, just quite confused. Any help is greatly appreciated.
Hello Tyler, A pulse can be defined either positive or negative - it is all relative. Most parking / emergency brake circuits are "negative / ground". What this simply means is that by engaging the parking brake, a ground is signal is sent to an indicator (parking brake light).
The 9411 software is designed to see a "window" of ground pulse(s). There are two situations in which the parking brake sequence can be started; parking brake engaged or parking brake disengaged. If the parking brake is applied before the ignition is turned on, this is the preferred method because it is easier to hit the ground pulse "window".