This makes no sense to me

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=27055
Printed Date: May 25, 2025 at 4:03 PM

Topic: This makes no sense to me

Posted By: nikkicv
Subject: This makes no sense to me
Date Posted: February 23, 2004 at 4:29 PM

Hi guys,

Trying to work out some things with my alarm install to finalize it. Today I had some time to tackle correcting the hood pin switch that would set off the trunk ajar light in my 99 Hyundai Accent's dash.

Originally I had the trunk switch (used the factory switch for the dash indicator) and an aftermarket pin switch for the hood tied to the (-) instant trigger input of my Viper. I learned by reading this site that you could stop the hood pin from setting off the trunk ajar light by diode isolating the hood and trunk switches from each other. So today I used a pair of 1N4001 diodes that I twisted the anode side leads together to form a "Y" like I saw here, and soldered the twisted pair to the (-) instant trigger wire from the alarm harness. I then soldered the hood pin wire lead to one leg of the diode "Y" and the trunk switch to the other leg so that the diode bands face the switches.

So, I expected to no longer see the trunk ajar light when I popped the hood, but guess what, I do!?!? I triple-checked that the diode bands face the switches, and they do, but I am still getting the dash light. I don't understand! Can anyone help?:errr: What did I do wrong?

Replies:

Posted By: chriswallace187
Date Posted: February 24, 2004 at 1:02 AM

First a stupid question - were you absolutely certain that your doors and trunk were shut when the light was on?
Second - check the point where the inputs are soldered to the diodes to make sure they aren't accidentally making contact. Make sure you tape off each leg separately.

Posted By: Big Dog
Date Posted: February 24, 2004 at 8:58 AM

Hi Nikkicv,
First of all, I don't see a need to isolate. Who cares if the light comes on with hood open? It's not like you drive with the hood open that the light would bother you.
You can't harm the electronics in the car by grounding a wire that requires a ground.
Also, if the light comes on while driving and you're convinced that the trunk was slammed shut, that little light could keep your car from looking like an opened can of spam! It's a win/win!

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Posted By: JMaxx93
Date Posted: February 24, 2004 at 4:58 PM

:thumbsup: great thinking

Posted By: nikkicv
Date Posted: February 29, 2004 at 9:43 PM

Final diagnosis: BAD DIODE!

Only thing I can think of is that I had heat on it too long while soldering... Pulled it apart today, made a new "Y" with a pair of fresh diodes and everything works the way it should now.

BTW - Big Dog, my reason was not just because of the indicator light. I'm using the factory trunk switch, which is +12V when closed and 0V open, with a simple pin switch for the hood (open circuit when closed, grounded when opened) with both tied to the same instant trigger input to the brain.

I gotta admit you have a point though, and I could have just put the one diode on the trunk lead! posted_image