Key Fob Mod LED - My First Mod...

[Buhmblbe]

So I'm up late and thought "what can I do with the kids' toys that they don't play with anymore and my conclusion...attempt a mod for my key fob and not totally break the thing in the process. Bear in mind I have little to NO experience with electronics or doing mods so be gentle on the comments. That said...here's what i did...I decided to add an LED light to the keyfob for night time use. Why you ask...why not, it seemed cool to me.

Step 1: I removed a small red LED from a dragon's mouth from my son's unused toy...I used red because it doesn't damage night vision.



Step2: Carefully drill holes in the key fob to thread the wires from the LED from the top of the key fob into the battery compartment...therefore you need to drill two holes...one on the outside top corner and one on the inside within the battery compartment.




Step 3: Thread the wires through the holes you made



Step 4: Route the negative wire around the top of the battery compartment and then into the battery compartment. You'll need to snip some plastic away to get the wire through and into the battery compartment itself...see the pictures(sorry for the blurriness). Secure the wire at the snipped pass through with some Krazy glue so it doesn't move out of place.




Step 5: Make some kind of a button through the battery compartment cover that will bring the positive wire into contact with the positive side of the battery. You'll need to cut away some more plastic here. I disassembled a different keychain LED thingy that my daughter got for me many a moon ago and was just laying around doing nothing. I'm guessing that all you electronic wizards have much better solutions for this but it seemed to work somewhat well for me. The trick was keeping the positive wire off of the positive side of the battery until the button was actually depressed down and of course you then need to have the positive wire dissengage from the positive side of the battery when you let go of the button. This part was a real bear for me for whatever that's worth.


This thingy down here was the "spring" from what I could tell for the button. I used more Krazy glue to secure the metal part to the cardboard ring it sits on so they wouldn't separate easily.(You can't see it here but the cardboard is actually a ring like a donught with no center)


Step 6: Route the positive wire into the battery compartment...again you'll need to snip some plastic away to get the wire in there. Once in there, secure the positive wire onto whatever button device you use(I used Krazy glue again attaching the insulated portion of the wire onto the underside of the ring(sorry no pic of that one.)




Step 7: Put the battery cover back on...I know my plastic has frilly fringes on the outside....I'll try to smooth it out with a little sandpaper tomorrow. Also, I realized that the way the positive wire is routed in the diagram it makes it difficult to fully close the battery compartment. More plastic trimming on the inside(like a small trough) should fix that.




Step 8: Amaze you and your friends at the wonder of a small functioning red LED light on your key fob



Ok...so now I'm tired. I hope you liked the mod...I'm off to nighty night.

[AlSuwaidi]

wow.. creative and a good job! i wouldnt do it to mine.. but i still love what you did!

[Buhmblbe]

So I tested all the buttons...unlock,lock etc. and they all worked so I figured all was well...wrong:(. When I tried to start my car this morning it wouldn't turn on. I got the untouched key fob and it started right up. Then I put the "good"key in the house and tried starting the car with the modified key and hallellujah it started, BUT...half way to work I realize that the immobilization light is glaring at me on the dash. When I got to work I shut off the engine and then attempted a restart only to get three blasts from the horn and no start. I'm guessing 1 of 2 things here...
1-I need a new key fob and my midnight project will cost me dearly
OR
2-I need to reprogram/pair the modified key fob back to the car

Needless to say I'm bummed out over this set back. For what it's worth I will add that at the begginnning of the project I tried to open up the key fob(without success) and maybe that's what did it to the transponder OR maybe I drilled into something when I made the pilot holes for the LED wires, but I really was careful and don't believe I did that. I also took an x-ray of the interior since I couldn't open it to try to evaluate if something big was in my path of wires.(I'm a dentist so I have xray vision

[guyjusthere]

Looks like you hit the transistor that is inside of the key. you may have drilled it. Possible that the loss of power to the key = a need for reprogramming...

More possible that you cracked or cut the transistor that acts like a key's ID code... Dealer reprogram shouldn't be too expensive

Do you play with your xray often... looks like fun!

[Buhmblbe]

I'll try the reprogram first. Anyone know the procedure for this so I can avoid bothering the dealer?

[buzzy56]

Okay who was it that said those dam Xrays will eventually kill ya? Just kidding.Nice idea but just a little to risky for me.Should of used a cat scan?

[ron10]

love your idea.i was going to say i wouldn't have the guts to try and do it.now with what you are into,i know i wouldn't try it.hope you can fix it.i haven't priced a new fob,but i'll bet they are expensive.

[keydude]

Looks like the transponder in the fob is cracked. Once it is damaged, reprogramming won't help. If you start the car with the good key and then immediately turn the damaged key the car will start and run, but the immobilizer light will come on. Once you turn the car off, it won't restart until you use a good key. If you have your keycode, I can cut you a new key and help you program it without going back to the dealer. If you don't have the keycode, send me the damaged key and I will decode and duplicate it for you. I cut these keys all the time for our local dealers, they don't want to wait for a special order key. Let me know if I can help.
Mike

[Onereign]

To program a key, use a working key to cycle the ignition twice (don't have to actually start the car), remove the working key and then cycle to key to be programmed twice and voila! new working key!

[Buhmblbe]

Thanks onereign...I'll try that when I get home today.

[keydude]

If it works the dash will give you a readout and tell you how many keys are programmed.

[Buhmblbe]

I tried the reprogram...The car at least almost started. I got a short engine try and then it cut out. Better than the nothing I got before but still no good. Newkey here I come.

[Coop 2010]

My dealer quoted $31.XX for a new fob, not including key, key cutting , or programming. From what I read it sounds like all you need is a new fob.

Alot less expensive than I thought.

[HeavyD]

This mod will void your warranty!!! Just kidding! Cool mod!