So to give some background, I was sick of accidentally popping the boot and tripping the panic alarm just by bending over with my keys in my pocket, so I decided to add a switch so I can disable the key fob easily. This thread should show you how I did it.

*Note - I used a cheap aftermarket key fob, as I didn't want to destroy a genuine one if it went wrong. This means I know it fits in the aftermarket ones, but with the difference in battery holders between the two, I can't guarantee success with a genuine one. Here is the difference between the internals:

Genuine:



Aftermarket:



Tools needed:
Soldering iron, wire cutters / strippers, drill / dremel, small hobby files (optional), X-acto knife (optional), something to pry open the key fob.

Parts:
Key fob that you don't mind damaging, new battery holder, switch, some wires.



Firstly I opened up the fob, removed the battery, and desoldered the battery holder from the circuit board:



Then I took the back part of the case, worked out where the battery holder would fit best:



Then marked and drilled a hole for the switch:



The hole can then be shaped with a dremel stone, small file, or even a sharp knife. I used a combination of all three, but whatever floats your goat.

After I soldered some wires to the switch:



I then test-fitted the switch to make sure it would work and had enough room to slide on and off:



Once I was happy with that, I glued it in place with some epoxy resin and soldered the wires to the battery holder:



Once that was in place, I made up some more resin and affixed that too. I then trimmed the wires and soldered them to the board where the original battery holder was located:



Then it was simply a case of fitting the battery into the holder, and reassembling the key fob. If you did everything correctly then Robert should in theory be your Mother's Brother.

*Note: I did have to grind down part of the new battery holder as the metal tab for the positive terminal was sticking up a bit far and would come in contact with the negative on the board, shorting it out. Easy fix though with a grinding stone on the dremel.

Finished product is working perfectly and I no longer need to worry about scaring myself half to death by tripping the panic alarm while I'm leaning inside the engine bay

well done!




only one part you forgot ........ sorry


at the worst case you will get some dirt/dust/moisture in the opening

It can't go past the switch - I sealed it with resin on the inside, that's how I glued the switch in place. Yeah some dust could get into the switch, oh well I could probably make a tiny rubber boot for it but I'm not that fussed