Key issues

[RolfGolf]

Just wondering if anyone has encountered a similar situation to this.

My car did not come with remote central locking. I have a key which has a little crystal cylinder thing in it and when I purchased the car I was told without this little crystal in the key the car wouldn't be able to be driven.

Tonight on opening the old key to swap the crystal into a new key I had cut this afternoon, I discovered the crystal wasn't there ... I went out to my car with the old crystal-less key and put it in the ignition and the car started with no fault code ... I tried the new key which has no crystal and the fault code and immobiliser warning light came on.

What is going on? How come my old key without the crystal still works to start my car with no fault code?

Has anyone else experienced this?

[mikk]

if you use the new key in the ignition, but hold the old key next to it, does the car work like normal?

i'm thinking there has to be a transponder chip (crystal) somewhere, maybe you just didn't notice it? they can be black and glued in place, making them hard to see inside the key housing.

[JustCruisn]

If your 'old' key is the type with the bush button light, that easily splits open. Then you may have mistaken the light bulb with the crystal. The crystal is alot smaller than the light bulb and is glued in place on the left of the key.

[RolfGolf]

Hi Mikk, thanks for the reply - just tried holding the old key next to the new one as you suggested and couldn't start it. Then thought I'd open the old key again - in bright daylight - and I'm embarrassed to say the crystal is like you say glued in place and just hard to see

Didn't help that my previous battery had leaked over it either ... Looks like a trip to the optometrist is in order.

Good to know that my car is not possessed with magic key identifying skills that cannot be explained ...

Thanks again.

[JustCruisn]

Is this the key you have ?



In this pic the bulb is in place but the crystal is missing.

[RolfGolf]

Is this the key you have ?



In this pic the bulb is in place but the crystal is missing.

That's the sucker! Battery had leaked making it hard to see the crystal on the other side, though it might be something to do with my mince-pies (eyes) too ...

On a side note, has anyone swapped the globe for a led in these things - is there much involved?

Best Wishes.

[mikk]

Two ways...

Complicated way that keeps the same battery but will have even illumination over the life of the battery, and use less battery:
http://www.summet.com/projects/keylight/index.html

Other way:
let me know what size battery is in there now and I will tell u what 3V lithium battery you can use. after that you just need to work out how to wire in the led - white led is best for 3V... i'd recommend using a resistor for other leds

[RolfGolf]

The battery that was in there was a PX625A 1.5V Alkaline ... The complicated way looks ... well, complicated - I think the simple way is probably more where I'm at with this.

[mikk]

slow reply... just found this thread again randomly

but here's the answer. get a cr1632 lithium coin cell. u can get them cheaply on ebay (couple of dollars). get a bag of many 3mm white leds from ebay or just get one from jaycar.

first check that the leds lights up when one leg is in contact with each side of the battery at the same time. it will only work one way. if ti doesn't then flip the battery over. once you've confirmed that the led and battery are happy together, we just want them to be happy together inside your key.

now this is the hardest part... solder the led to some short wires inside the key, similar to the way it was done in the other guide, but without the other components. you will just be using wire to connect the led to the insides of the key.

alternatively, u can actually do it without soldering if you wrap one of the led's legs around the spring and one around the copper part. make sure the 2 legs won't ever touch each other though! mayeb u want to use something to protect the legs like plumber's tape or just glue it all in place.

put it all together and that's it!

things to note: u might kill the battery quickly if you hold the button on for a long time (10sec+). it will last longer if u just give it bursts. it probably is similar to the original battery life though since the led is more efficient but this is a signigicantly smaller battery. if you hold it for too long, (perhaps a couple of minutes?) u might also kill the led, but that depends on how much current (mA) the led you get can handle. generally that won't be a problem since we're talking about tiny batteries and minimal voltage for the led, and most people don't hold the button down for a very long time.