Tying Neutral Safety Wire into Hood Pin Q

Home / the12volt's Install Bay / Car Security and Convenience / Tying Neutral Safety Wire into Hood Pin Q (

Topic Closed)

Welcome Guest :)

Members

Next Page > < Prev Topic Next Topic >

B94Sport

Member - Posts: 22

Joined: June 10, 2003

Location: United States

Posted: July 26, 2004 at 2:49 PM / IP Logged

I would like to tie the neutral safety wire off of my ECU into my hood pin shutdown switch on my alarm, so that the remote start will not activate unless the car is in neutral. This is on a 6 speed transmission (Subaru WRX STi) that already has a neutral position sensor built in. I have heard that the neutral safety wire should be tied into the hood pin shutdown using a diode, but I don't see how it can work...

The hood pin currently shows 12 volts when the hood is closed, and ground when it is opened (magnetic hood pin). The neutral safety wire shows 12 volts when the vehicle is in neutral, and ground when in gear.

If I want to wire both of these to the hood pin input on the alarm, how can I make it so that everything still works correctly? It seems to me that if the hood was open but the the car was still in neutral, it would be possible to remote start it because the hood pin input on the brain would still see 12 volts from the neutral safety wire. Likewise it would still be possible to remote start the car if the hood was closed but the transmission was not in neutral, because the hood pin input on the brain would see 12 volts from the hood pin. How can I use diodes to isolate these two inputs from one another, and make it so that if one of the inputs is throwing a ground, the brain input sees ground?

draasch

Gold - Posts: 2,172

Joined: February 07, 2003

Location: Florida, United States

Posted: July 26, 2004 at 5:44 PM / IP Logged

what unit are you using????? most units have a SNS wire....and a hood pin switch wire....

Good Luck

David

Ace Security

813-376-9778

Tampa

Donate to the 12volt

B94Sport

Member - Posts: 22

Joined: June 10, 2003

Location: United States

Posted: July 26, 2004 at 6:16 PM / IP Logged

Oh, I am using a Compustar 2WSS-AS with the CM3000 brain. It only has a hood pin input, no NS wire input.

B94Sport

Member - Posts: 22

Joined: June 10, 2003

Location: United States

Posted: July 27, 2004 at 5:55 AM / IP Logged

bump

profuse007

Gold - Posts: 2,015

Joined: October 20, 2002

Location: Texas, United States

Posted: July 27, 2004 at 7:57 AM / IP Logged

-im assuming you let the brain to function on automatic tranny since you have NSS.

-so tie the hood and NSS w/ a diode facing the hood pin and another one facing the NSS computer module.

-whats the exact model of this Subaru?

-whats the wire for the NSS and its location?

Houston,TX

"The two most common elements in the universe are H+ and stupidity" (Ellison).

B94Sport

Member - Posts: 22

Joined: June 10, 2003

Location: United States

Posted: July 27, 2004 at 9:27 AM / IP Logged

Exact model: 2005 Subaru Impreza WRX STi

NSS wire and location: Pin 9 on B137 connector at the ECU. Don't remember the exact colors, but I have it marked off.

profuse007

Gold - Posts: 2,015

Joined: October 20, 2002

Location: Texas, United States

Posted: July 27, 2004 at 10:45 AM / IP Logged

thanks

Houston,TX

"The two most common elements in the universe are H+ and stupidity" (Ellison).

JWorm

Platinum - Posts: 2,208

Joined: December 11, 2002

Location: New Hampshire, United States

Posted: July 27, 2004 at 9:00 PM / IP Logged

B94Sport wrote:

It seems to me that if the hood was open but the the car was still in neutral, it would be possible to remote start it because the hood pin input on the brain would still see 12 volts from the neutral safety wire. Likewise it would still be possible to remote start the car if the hood was closed but the transmission was not in neutral, because the hood pin input on the brain would see 12 volts from the hood pin. How can I use diodes to isolate these two inputs from one another, and make it so that if one of the inputs is throwing a ground, the brain input sees ground?

The 2 diodes you install prevent the +12v from ever going to the alarm brain. Only the ground from the hoodpin, the ground from the NPS (Neutral Position Sensor) or both goes thru to the brain. I suggest clicking the link on the top left of this page that says "diodes" and doing a little reading.

If anyone wants more info on Neutral Position wires for Subaru, I could probably help you out with location/color of wires. I have info on most Subaru's from the last 5 years or so.

B94Sport

Member - Posts: 22

Joined: June 10, 2003

Location: United States

Posted: July 27, 2004 at 9:27 PM / IP Logged

JWorm wrote:

If anyone wants more info on Neutral Position wires for Subaru, I could probably help you out with location/color of wires. I have info on most Subaru's from the last 5 years or so.

I read that Diodes link, and still don't see how this can work... If only grounds go through to the brain, how will the brain get the +12 volt signal when the hood is shut, the car is in neutral, and thus should start?

JWorm

Platinum - Posts: 2,208

Joined: December 11, 2002

Location: New Hampshire, United States

Posted: July 27, 2004 at 11:21 PM / IP Logged

The brain doesn't need to see +12v in order for it to remote start. It just needs to NOT see a good ground.

Next Page >

Printable version

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

Search the12volt.com

Follow the12volt.com

Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.