My wife just bought a 2009 Mazda 5, and as you know it came with two keys... those big klunky keyfob with the pop out key. Eyuck! I don't drive her car very often and I don't want to have to carry around this mini brick of a key, but I do want a key on my keyring so I can drive her car if I need to.

The dealer would not throw in a third key, so I found a mazda 5 transponder key blank on ebay for $10 + $7 for shipping. Took it to my local hardware store and had them cut it for $4. Then programmed it myself. Total cost for my third key was $21.

Here's how I programmed it. Note that this only works if you already have two working keys. Have all three keys sitting on the passenger seat, as you have to do these steps within a few seconds of each other.
1 - Insert Good Key 1 and turn to the On position (do not start the car) and wait for the security icon (the car with the padlock) to go off (about three seconds.) Remove Good Key 1
2 - Insert Good Key 2 and turn to the On position (again do not start the car) and wait for the security icon to turn off. Remove Good Key 2
3 - Insert the unprogramed third key and turn to the On position. The security icon should be lit for a few seconds, then it will flash on and off a few times, and then stay off. Remove the Third key. That's it, you should now have three keys that will start your car.

Seems that this is a pretty standard process to program a third key, as these steps also works for most Ford and Mercury cars as well.

RWB

 

Yes, this works for the earlier cars as well. That's how they programmed my third key. (I was in the car and he showed me how to do it then.)
But in '04 when I bought my third key from the dealer, it was only $32, and they cut it and programmed it too. No extra charge. Even at that I thought to myself that I had never paid that much for an extra key before in my life. Nor did any of them need to be "programmed."
I now know just how lucky I was and "what a deal" I got then.

Those flip keys are a pain, I know, but I have the "fat" key w/a separate fob for the locks. It's not much better from your pocket's standpoint.

 

Thanks for the tip! I just bought one on ebay just now (got this one: http://bit.ly/mazdakey) I saw some that were cheaper, but this one *appears* a bit less cheap, and has mazda logo... shall see when I get it. Fingers crossed that it all works as planned

 

^^^^

Link to eBay seller where you got the key?

The one in the above post is in China.

 

I just tried this and it didn't work so well for me. I took my key to a local locksmith to cut. It looks fine to me, however, the key does not does turn in the ignition (key goes in, but does not turn). I also tried the key in the door and the key doesn't even go in completely, it stops half way.

This is likely a bad cut from the locksmith, but I used some play doh to see where the bad cut was since I can't see a problem with the naked eye. And I can't find anything wrong. I'm going back to the locksmith today to see if he can do anything to fix this.

Anyway, if you're thinking of doing this, you might want to take your key to the dealer to have it cut or at least someone who specializes in these keys.

 

Kueifan - definitely the cut from your locksmith is the reason the key won't turn...... I just got my key last week (from Hong Kong) the locksmith cut it, and it turned no problem. I programmed it, and it works perfectly!!!!

 

Thanks for the reply BCNorth. Turns out the issue was not the cut of the key, at least not from the locksmith.

The key has a ridge that runs down the length of the key, this turned out to be too wide and I had to file it down. It was the same issue as in this forum. Once I filed it down a little, the key worked. When I mentioned earlier that the key went in to the ignition, it probably wasn't all the way in, as was the case with the door keyhole.

I got my key here in case anyone's looking for a source.

 

Will this work if you only have one key? Just leave out step #2?

 

benmunger, this will only work if you have 2 working keys already and are making a third. If you only have one key and want a second one, I think you'll have to go to the dealer.