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Hi all, as suggested I am adding this to the stickies to help others find the information if they need it.

This should apply to pretty much all car remote key fobs where one or more buttons no longer work. If you press the button on your remote and it feels spongy, doesn't make a tactile click sound/feel and doesn't operate as it should; then there's a good chance you have worn out buttons in your fob that may have even gone as far to fall apart.

Although this guide should apply to all fobs, I have done this on a 3 button fob for my S-Type, like the one pictured.
Input device Camera accessory Gadget Peripheral Rectangle

The buttons for my fob are SMD (Surface Mount Device) tactile buttons, measuring 4mm x 4mm x 1.5mm, this is a fairly common size and you can buy a small pack of 10 on ebay for around £2, I'd advise getting more than you need as they are small and it's easy to loose one. They look like this:
Camera accessory Auto part Automotive lighting Font Bag

Firstly stick a coin in the slot on the end and open the fob up, once it is in 2 halves you can push one of the buttons in to remove the rubbery inner case and get the circuit board out.

On taking mine apart it was apparent that the buttons had fallen apart as the plastic inner section could be seen along with the contact, all of which covered with 18 years of dead skin and dust :-?

Use a pair of tweesers to hold the button (ideally you will use ceramic tweesers as this will stop any shorting out components while working) while you desolder the button, the tweesers can also be used to lever each corner up as you desolder it. Once the button is removed, gently scrape the soldering iron over the solder pads on the board to remove excess solder (this will help to get the new buttons flat), if you have it some solder braid will help remove any excess solder. You may notice that I've lost a solder pad on one of my buttons, luckily the pad that's missing is one that is only used to anchor the corner of the button down and serves no electrical purpose.

Now for the fun part, while holding the new button in place with your tweesers, apply a small amount of solder to the end of your soldering iron (this isn't the advised way to solder as it will burn the flux from the solder, but it makes SMD easier) and dab the solder onto one of the pads to secure the button by one corner. Now you can solder the other corners in the normal way by heating the pad with the iron and applying solder directly to the pad. If you can manage it, hold the tweesers on top of the button while soldering to keep it flat to the board. If you are struggling with this you can use a dab of superglue to glue the button in place, then solder the pads, just remember that this will make it difficult to replace the buttons in the future if they ever need doing again.

If all has gone well then your fob should now have working buttons. You may need to get the fob re-programmed to your car as many have reported fobs loosing programming after a couple of minutes away from the battery. I must have been very lucky though as mine was apart for around 20-30 minutes and worked perfectly once put back together.


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