Hi all, been coming to this site loads for brilliant d.i.y's. I finally have something useful to share back.
My diamond shaped key fob started becoming weak and finally stopped working altogether. I rang BMW to see how much a new battery would cost. They said they were not replaceable and a new key would be needed, £120 plus V.A.T. I didn't want to pay this and having nothing to lose I looked towards a d.i.y.
I bought a new battery of eBay for 4.95, I cut open the key with a kitchen knife (it took about an hour of carefully slicing). I knew the battery was soldered on and I knew there was a 60 second time limit to change batteries. I took the circuit board and new battery to work the next day to let the electrician do the change as it was more his skill. He came back to me saying the battery was the wrong type, he checked the volts on the batteries anyway, the new one was 3 volts, the old one was 3.2. So he knew the old battery was in good condition still and checked the circuit board. He found the negative pin on the underside of the board had a dry solder joint. He cleaned it off and put some new solder on it.
The key worked fine, just superglued the case back on and its perfect, except for a few rough edges from cutting it open. Total cost £4.95, which wasn't needed
I hope this hopes some people as I didn't come across anything like this when googling and searching.
My diamond shaped key fob started becoming weak and finally stopped working altogether. I rang BMW to see how much a new battery would cost. They said they were not replaceable and a new key would be needed, £120 plus V.A.T. I didn't want to pay this and having nothing to lose I looked towards a d.i.y.
I bought a new battery of eBay for 4.95, I cut open the key with a kitchen knife (it took about an hour of carefully slicing). I knew the battery was soldered on and I knew there was a 60 second time limit to change batteries. I took the circuit board and new battery to work the next day to let the electrician do the change as it was more his skill. He came back to me saying the battery was the wrong type, he checked the volts on the batteries anyway, the new one was 3 volts, the old one was 3.2. So he knew the old battery was in good condition still and checked the circuit board. He found the negative pin on the underside of the board had a dry solder joint. He cleaned it off and put some new solder on it.
The key worked fine, just superglued the case back on and its perfect, except for a few rough edges from cutting it open. Total cost £4.95, which wasn't needed
I hope this hopes some people as I didn't come across anything like this when googling and searching.