I'm trying to understand just what exactly is going on with my 1967 Newport. I am in the process of installing a car alarm. I want to use the dome light to trigger the horns(instead of siren).
I can use a switch to ground or a switch to 12v as the trigger, however the factory dome light circuit seems to have no ground at all. There are two wires leading to the dome light, Pink and Yellow.
I have a constant voltage at the Pink wire and the Yellow is nothing, no ground nor voltage when the door is open and voltage when the door is closed. So, therefore, both wires have voltage to the dome light when the door is closed. Where is the ground? and how can I get the signal I need to trigger the alarm?
I think I can put in a relay, but then it would have a constant voltage on it til the door is open, which then it loses voltage rather than gaining a ground or 12v. Will that relay with a constant voltage act as a load and put a tiny drain on the battery? Have I confused anyone yet?
I can use a switch to ground or a switch to 12v as the trigger, however the factory dome light circuit seems to have no ground at all. There are two wires leading to the dome light, Pink and Yellow.
I have a constant voltage at the Pink wire and the Yellow is nothing, no ground nor voltage when the door is open and voltage when the door is closed. So, therefore, both wires have voltage to the dome light when the door is closed. Where is the ground? and how can I get the signal I need to trigger the alarm?
I think I can put in a relay, but then it would have a constant voltage on it til the door is open, which then it loses voltage rather than gaining a ground or 12v. Will that relay with a constant voltage act as a load and put a tiny drain on the battery? Have I confused anyone yet?
