350z unlock signal

I rebuilding my car computer setup and installing carnetix 2140 regulator that I can turn on using an external pulse (<.2v or floating to 2v-20) (https://www.carnetix.com/installation/P2140_Users_Manual_V1_2.pdf section 6). Another option is momentarily shorting two pins on the board.

What I am trying to accomplish is booting up my carpc when I unlock and/or disarm my alarm. It looks like there is a lt blue wire that is pulsed once for disarm and a second time for unlock. The wiring info on this site (https://www.the12volt.com/installbay/forum_posts.asp?tid=8149 easier to read link at https://www.directwholesale.net/diagrams/printpage.asp?ModelID=19784&MakeID=5 ) seems to indicate that my car has a 3 Wire Negative system?

My first question is can I tap into this wire to get a momentary voltage change when I unlock the car with the remote?

I am thinking that the wiring info means that the lt blue wire is at ground normally and +12V (momentarily) when I press the unlock button on my remote. If this is the can can I just tap into this line (possibly with a diode for safety) to accomplish what I need?

If it is the opposite, (+12V normally and ground pulsed) then I would need a relay correct?

I don't think that's quite what you want.

--The blue wire mentioned, inside the driver's door, will make a ground pulse ONLY each time the KEY is turned inside the driver's door.....it will do nothing when you use the remote.

You want this computer to boot up when you unlock with the remote keyless entry, I'm assuming?

--The wire that controls the electric motor to unlock the door, goes from the BCM inside the car, to the motor inside the door.

This wire will rest as a ground, and them make a momentary positive pulse every time the doors are unlocked electrically.

This wire will see power under any of the following three conditions:
~when you unlock the door with the remote
~when you unlock the door using the switch inside the car
~when you insert the key in the driver's door, and turn it TWICE to the unlock position.

Anyway, this wire is listed as yellow, and in a different location depending on the year of your Z:

2003-2004:
Yellow wire, white plug at pin 23, at BCM (Body Control Module) in the driver kick panel below the fuse box.

2005-up:
Yellow wire, BCM in driver kick panel, pin 44.

Thanks Chris, I will take a look at it later on today.

Okay, I found the wire, and verified the pulse is what I need. As far as attaching to this wire I am thinking that I should try to pop the pin out of the white connector and solder in a wire of my own to run to my power supply.

Why take the pin out of the connector? Strip a little insulation back and solder onto the wire there. Once those pins come out, they don't always go back in so nice.

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Yeah, I wouldn't take the pin out.

You will encounter a LOT of debate about which connection is best, but here are your basic options:

--strip some insulation off the factory wire. Poke a hole through the middle of the wire strands with a test light or meter probe. Push your new wire through there, and wrap it around. Solder. Wrap with good quality, name-brand electrical tape.

--same as above, but without solder.

--use a T-tap or Scotchlok connector. These connectors disturb the factory wiring less, but they don't look as nice, and many people consider them to be less reliable.

I am bad enough at stripping wires (and soldering) as it is, and this is a pretty tight place with a fairly short wire. The T-Tap seems like the hardest one to mess up, so i think i am going ot go that route.

One thing to watch out for here is the fact that some voltage will be present on that wire when you lock the car, too.  It won't be a lot, but it will be more then 0.2vdc.  It may at times approch the 2vdc minimum that is stated above.  I would be concerned with their 'deadband' listed, as many times a dead band indicates unpredictable operation.

You may want to consider running a relay off of this wire to eliminate the negative effects of powering a reverse polarity load.  That would give you a  true floating when off/12vdc when on signal.

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Kevin Pierson

I think I will hold off on the relay until I determine if it is a problem. I am going to be running it across a diode and a resistor, so I am looking at needing at least 2.7V to trigger.

If by deadband you are talking about the 2v-20v range, i think that it is more about working with a large range of voltages. The regulator is designed to work with a wide range of vehicles (12v and 24v). The guy who makes it supports it really well and he is pretty quick with firmware changes if one should become necessary.

The deadband is the range between 0.2VDC and 2VDC where the operation isn't specified.

What happens if there is 1vdc on the wire?

The diode and the resistor should help out a bunch.

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Kevin Pierson