DIY: Use New Smartkey with 2005 Nissan Altima

They said it couldn't be done! Definitely a ghetto mod on the inside but oh so worth it on the outside! **This is NOT for the faint hearted!** The new Nissan/Infinity SmartKey or iKey is not compatible with older Nissan/Infinity cars . You can find switch blade FOBs on eBay but Arati really wanted the cooler looking SmartKey for her 05 Altima. With this mod what were basically doing is taking out the guts of the old FOB, modifying it and putting it into the SmartKey's Fob housing. I got most of my information from this post but the FOB in the post had a different circuit board so the solder points are different. Some Caveats: These instructions are not detailed. I'm too sleepy to type details. You need to know a bit about electronics and soldering to survive this. There are two types of smartkey housings and there are two (maybe more) types of old fob circuit boards. But lucky you, between this post and the one above you should find your answers! I would recommend trying this on a spare fob incase you solder through the board! I however have no patience so I started on the one and only fob that Arati has. Before I started I tested all the contact points that I was going to use by shorting them with a wire and checking if the car responded. Tools: A pair of pliers and scissors help too! The FOBs: Why we're doing what we're doing Since the buttons on the Smart key are spaced differently from the old fob we need to make up for this by replicating the button contact area in the right spots. The panic button is the only one we wont need to move since it lines up (almost) perfectly with the new fob. The contact area is basically two wires (+/-). When a button is depressed the little back dot on the plastic sheet touches the two wires and completes the circuit and beep beep the car responds. The How To: First lay down two layers of sticky tape over the front of the circuit board to prevent any shorts. Take strands of the 16 gauge (or similar) copper wire and put them through the holes in the front and solder at the points identified at the back. I used the sticky tape to secure the wires and to make sure they didn't touch each other or move.
The Front - poke the wires through these holes
The Back - Solder the wires at these points (if your Circuit board looks different refer to the post above)
Here is a mid-way shot. I still have to solder the lock2/unlock2 and the battery thingy.
Here is the back all done
And the front all done:
Now arrange the wires as shown. Some things to remember:
  • Cut out the tape above the Panic Button. We will be using the original button area for this button.
  • Compare the button location and area against the new housing to align your wires correctly
  • Be sure to cut out the tape at the contact points - these will be your SmartKey FOBs button contact area.
At this point I tested the mod by putting in the battery (taped it to hold it secure) and checking each contact area one at a time by placing a contact dot from the plastic sheet over the contact area. Might be a good idea for you to do so too! Next was the point of no return for me coz the soldering was great for me but now I was cutting up things! Cut up the plastic sheet with the contact dots from the old FOB and place them over the contact wires. This is a pre-shot. I had to cut the plastics further as I tweaked it to ensure that the contact area aligned with the buttons properly. I don't have a picture of the next part but you can check this picture out from the thread above to get an idea. I ripped out the tactile switches from the new FOB's circuit board with a pair of pliers. I laid a line of sticky tape over the contact dots and stuck the switches over the contact area. This is because the buttons on the new FOB are set in too deep and we need a filler so that the buttons can make contact with the contact dots. I stuck a rubber square for the panic button. Aligning the contact points is the toughest part of this mod. I took me a long time to get it perfectly aligned so that the buttons respond when pressed with normal pressure. On the housing I had to break off some bits that held the battery in place to allow for the mod's circuit board to fit. A pair of pliers will do nicely here. The forum post suggests removing the rubber button layer so that the case can close completely. I didn't really want to do that since the FOB wont be waterproof without the rubber layer. I had to rip out all the obstructions in the housing and file down some edges of the circuit board and the surface of the housing. Do what you need to. After all is done, close the case. I managed to close the housing almost a 100%. but you don't really notice coz you're admiring the shiny new FOB :)