door trigger diode isolation

Hi All, I dont know an awful lot about electronics, but I know just enough to be dangerous :) I am looking to do the ol' diode isolation trick to stop my dome light playing havoc with the alarm in my 01 Subaru Outback; following along the lines of The question I have is... It looks like I can put the diode any where between the door switch/trigger output and alarm input.. To save pulling my dash apart and trying to find where the guy that installed my alarm hid it, can I put a diode directly behind the door light switch in the pillar of each door jam? Hmmm Many thanks in advance James

You shouldn't need it so how is your dome light playing havoc? More likely a faulty door switch.

thanks for your reply when i arm my alarm while the dome light is fading out it puts it into zone by-pass mode and makes all sorts of beeps to let you know. it arms fine once the dome light has gone out. i just hate the attention it attracts when it makes its wee song and dance to let you know its in zone by-pass, and im getting sick of standing around for 30 secs while i wait for the light to go out! Thanks again :)

The installer should have seen to that, either with his install or programming a dome or courtesy light delay on the alarm.

yeah, dont get me started on him!! unfortunately the alarm doesnt have that function to program, so i was looking for the next best thing. reading up on this way looks to be pretty straight forward, i just wanted to confirm things before i started :)

That car shouldn't give any problems, just wire the door trigger wire to one of the door trigger wires, the use of diodes has nothing to do with it.

hmm im clutching at straws as to what it can be. whats all the talk about diode isolating for delayed dome lights all about then?

Nothing to do with the delay, it's when the factory uses processors and timers to control dome lights amongst many other things, these vehicles, like e.g. Fords use separated feeds from each door, tailgate and hood. They're known generically as body control modules. I did loads of Impies from around that time and had no problems. I suggest your man has taken his door trigger from the dome (courtesy) switched (via the door pins and a timer) rather than one of the door pins which should be adequate on that car. Japanese car manufacturers were very late adopters of these control modules, they got their electrics right in the first place.

Yup, it's just a matter of getting at the triggers before they pass through the processors, and a diode directly behind the doopr pins would make no sense at all.

that is great info guys!! thankyou both very much!! I was starting to pull my hair out! and thinking about it, that makes perfect sence!!! will let you know how I get on :) thanks again