sharing factory hood switch?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=104623
Printed Date: May 20, 2024 at 3:38 PM

Topic: sharing factory hood switch?

Posted By: katit
Subject: sharing factory hood switch?
Date Posted: May 10, 2008 at 1:26 PM

I have factory hood switch (located inside latch) which works exactly as needed (ground when disconnected)

I thought I will just connecto to that wire. But it goes to factory alarm module and for some reason alarm's side has ground all the time. So, simple connection doesn't work. Did somebody make this work?

Thanks!

Replies:

Posted By: chillin420
Date Posted: May 10, 2008 at 1:37 PM

use a relay to convert the current to match what you are installing

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you can do it....
advanced MECP, lol does it really matter....
patience is a virtue

Posted By: chriswallace187
Date Posted: May 10, 2008 at 3:35 PM

It depends on the particular vehicle - many cars I've tried to use the factory hoodpin (particularly Nissan and Hyundai) and the BCM or equivalent module puts out electrical pulses randomly, causing the remote start or alarm I've installed to see a false "hood open" signal.

In a lot of cases it's simpler and easier to just install your own hoodpin.

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

Posted By: katit
Date Posted: May 10, 2008 at 3:59 PM

I solved it. Schema shows that hood pin switch only goes to switch and then to the ground. So, signal that exists on CPU side doesn't do anything, it's just the way it is. I cut factory wire, installed diode and hooked Viper hood switch wire there. Works like a charm! Factory alarm works as expected, Viper sees what's needed. No issues.

Posted By: KPierson
Date Posted: May 10, 2008 at 9:08 PM

I would recomend always diode isolating the hood pin. If you are going to use one sensor to drive two inputs it is always a good idea to isolate the sensor.

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Kevin Pierson

Posted By: howie ll
Date Posted: May 11, 2008 at 12:03 PM

Diode original wire with bar away from switch, forward ie between diode and switch jon to your alarm, this will stop feedback from the BCM, oh I realised I just repeated Chris and Kevin, that's because they are always right! Don't worry I've finally found a source of Scotch 33+ in the UK at $6.50 per roll.

Posted By: katit
Date Posted: May 11, 2008 at 1:15 PM

howie ll wrote:

Diode original wire with bar away from switch, forward ie between diode and switch jon to your alarm, this will stop feedback from the BCM, .

I did like that, figured myself :)

Thanks guys!