Key fob repair

afternoon all,

My '96 VVC continues to give sterling service, its approaching 30,000 miles in my ownership now (in 3 years) and I wouldn't be without it.

It has, however, developed an odd fault.

I have two key fobs for it, and with new batteries and some soldering (as per the guides in this magnificent forum), both worked perfectly for over 2 years. Recently, one of the fobs won’t lock the car. It will unlock it with no issue, and the immobiliser is switched off by pressing the unlock button, so I can get the car started ok. Just that lock button doesn’t work. (the 2nd fob is fine in all respects, meaning that the ‘car-side’ of the system must be ok).

So my question is what’s wrong with it? My guess would be that the ‘lock’ button (micro switch) has failed. I see that fob repair kits are available on ebay for a fiver or so, which contains new micro switches, is it easy enough to strip the fob and replace just one micro switch? It strikes me that the fob PCB itself must be working for the car to unlock and work with the immobiliser, so this repair would be a lot cheaper than a whole new replacement fob plus re-programming costs?

I think you are probably right. It is worth a go if your soldering is up to it.

:yesnod:

Are the switches like these?



If so, they aren't particularly difficult to replace in a pcb (depending on your soldering skills, obviously. You should be able to check the operation of the suspect switch, in-situ, with a multimeter.

If this is what you need, they are cheap from ebay in a variety of sizes or, if you ask me nicely, I'll send you one FOC.

Bruce.

I suspect that the originals are lower profile & surface mount; this is going to require a fine tipped soldering iron & a fair amount of patience.

Go for it, let us know how you get on.

here we go, it's the button nearest the camera on the first picture, the second picture shows the back of the PCB. Unsoldering that is going to be a challenge (and you can see the results of my battery cage soldering!)

@Bruce, Legend.

I'll measure them and drop you line, Sir.

Those switches are surface mounted - i.e. they are mounted on the same side as they are soldered. You are going to need a soldering iron with a small bit (1mm) and fine solder (0.7mm). It would help, depending on your eyesight, if you could do the job under a magnifier.

The switches I talked about are 6mm square and come with various length buttons. Mine are a total of 7mm from the base of the switch to the top of the button. They look about the same as yours. The legs will need to be cut and bent to fit the solder pads but that's not difficult.

If you really aren't confident, I'd have a go for you but I'd make no promises...

Thanks for the offer Bruce, very kind but I wouldn't expect you to do that on my behalf. My own soldering iron is too big but a little one is about £8 on evil-Bay, plus the switch for a fiver. Still cheaper than buying a new fob & having it re-programmed.

Hmm, love a challenge!

Never one to rush into something, I eventually got around to this.

Well, I say I, I actually mean I took the fob and the new switch (courtesy of the link elsewhere in the thread) to the bloke who fixes mobile phones in town.

He has a tiny soldering iron, a magnifying glass and oodles of patience. He charged me £7 to fit the switch and it now works as it should.

TaffMGF wrote: Never one to rush into something, I eventually got around to this.

Well, I say I, I actually mean I took the fob and the new switch (courtesy of the link elsewhere in the thread) to the bloke who fixes mobile phones in town.

He has a tiny soldering iron, a magnifying glass and oodles of patience. He charged me £7 to fit the switch and it now works as it should.

Haha! That really is taking your time! I know that, if you have the soldering skills, it's not particularly difficult but £7? Total bargain!!!
:drive:

I know mate, I hadn't realised it was 18 months...

In my defence, I hadn't used the car that much and it has kind-of slipped down the lost of jobs t do on the fleet.

A fine-tipped soldering iron was going to set me back £10 plus some solder. He had a bit of a struggle with it as well, apparently. I paid with a tenner and told him to keep the change but he wouldn't have it. He's gone straight onto the good contacts list.