2004 Anti Theft fob Nissan XTerra

[steeveesas]

Hello all,

I bought a 2004 Nissan XTerra in 2005 from the dealer. The car came with an anti-theft mechanism that I don't think every really became popular and I'm having a terrible time finding a reference to what the thing is actually called and I need a new one (See image)

The way it works is this. It's a fob that according the the dealer electromagnetically completes the circuit when starting the car. The car will not start without this fob present (within 5 feet, and you have to press a button on the fob to activate it). The fob is not a remote key starter, I still use a mechanical key to put in the ignition and turn it. The idea was that if someone car-jacked you and stole your car, you would have this special starter fob in your pocket and even though they could drive off with the car, once, they got where they were going and turned off the car, they wouldn't be able to start it again since the fob is still with you.

I'll attach some pics of it. If anyone knows what this is or how I can order a new one, I'm in desperate need of one.

Alternatively, if there's a way to circumvent using this system altogether and just go to a normal starter system, I honestly would rather be done with it. It's causes nothing but problems.

I have two of these fobs and they've both finally broken.

Thank you so much!

[VStar650CL]

That has to be an aftermarket add-on, it isn't factory. Have a hard look under your dashboard for connectors that aren't factory. Most of those systems interrupt power to either the starter wire or the ignition circuit, so they're almost always located someplace on the wire bundle that feeds the ignition switch.

[steeveesas]

Thank you for your response.

I'm not much of a car guy, but you think if I take this to a mechanic they can replace it with something basic so I can use just the factory key? Should I go to the dealer for this?

[VStar650CL]

Anybody competent should be able to locate and remove it and reconnect the OE wiring. Since it's aftermarket, I doubt a dealer would know any more about it than the next guy, however, a dealer has easy access to the right wiring diagrams in case the installers butchered anything.

[steeveesas]

Thank you so much! I appreciate your response.

[VStar650CL]

[steeveesas]

One last thing on this subject. Shot in the dark here.

So basically I'm going to follow the advice given and look into getting rid of this after market key fob that has caused so much annoyance.
However first I need to get my car moved. If I can't get it started on my own, I'll have to have it towed. I'm hoping to avoid that and maybe learn something useful in the process.

I've attached an image of the innards of the key fob's electronics.
1. On the left, you''ll see the fob with a little rectangular metal cover with a black spot in it's center. The black spot is rubber and goes through a hole in the metal.
2. If you look on the right you'll see under the cover. There is a circuit connector (not sure of the terminology) which is metal. I believe there was a piece that is no longer there between the rectangular metal cover/black rubber piece and the connector shown. When my key dropped the other day, I believe I saw a piece come out and I can't find it anywhere. I have no idea what this piece would be or what it did, but now it doesn't work the same way.

Before when I would press on the black spot I could fill a soft resistance and almost like an inaudible tactile click. After I did this, I could start the car.
Now when I press there is no tactile feedback. I'm just pressing on something that doesn't move. This is true for both when the rectangular cover is on and when I simply try pressing on the piece under the cover with the cover off.

Does anyone have any idea how how I can temporarily rig this so that it does whatever it did before? Do I just need to put some metal on it to conductor electricity or something like that?[/img]

[VStar650CL]

The button basically just shorts between the two red arrows, you can duplicate a press by shorting across it with the tips of a tweezer. You might also need to hit the blue area with some contact cleaner, that grey stuff all over the IC pins appears to be corrosion.

[steeveesas]

I see! That makes sense, and what I was clumsily trying to say when I said "Do I just need to put some metal on it to conduct electricity".

Would the tweezers touch the places where the red arrows are or where the green arrows are (new image)? I'm guessing the button probably had a little piece of metal that came down and connected the pieces between the green arrows (The "circle" looking center piece and the rectangular gold bar just above it).
I'm guessing the effect is the same. Both probably short the circuit.

My car is across town marooned in a garage so I won't have a chance to try this for a few days but will let you know how it goes!

Thank you!

[VStar650CL]

Those are solder joints where the arrows are, they're metal. Just bridge them with a metal tweezer and it will be the same as closing the switch. Those little tactile switches usually have a tiny "belleville spring" style contact inside which inverts and makes contact under finger pressure, with inversion of the disc providing the little "snap" you feel when they engage. When the spring fatigues and wears out, they either stop making contact or collapse and make constant contact. You can probably find a replacement if you want to take measurements and browse through Mouser or Digi-Key. Lots of manufacturers make them.

[steeveesas]

That makes complete sense and is very interesting. Appreciate you explaining, it's interesting to me to learn how this works. Never was a car guy, but have regrets about it. It's interesting stuff.

My friend also found an idea online about using a magnet. I'm guessing it might be yet another way to short the circuit (pretty much the only thing I got out of an electromagnetics class I took 20 years ago).

But we'll give your method a go first!

[steeveesas]

After a long delay (being sick and work laden) I finally got over to my car across town and gave this a try.

It worked brilliantly! I just took a copper cable wire (<1mm diameter) I got from my friend (like those ones wound together in cables) and connected the central circular metal piece to the rectangular metal piece shown in the above diagrams and it sent the signal to the car's computer so that I could start it up without issue!

Thank you for all your help on this one! Saved me some time and money, and also taught me something cool.

Much appreciated!

[VStar650CL]