As is often the case, things stop working when fixing is impossible, expensive or just annoying. In the latter category, my Garmin HRM-run chest strap stopped working just when I was visiting the States. I figured it was the battery, but of course I didn't pack any batteries.
Garmin HRM-run chest strap, © Garmin
I bought some quite expensive Duracell 2032 batteries and replaced the old with the new. My watch however did not find the strap. I carefully followed the instructions on both Garmin's site and on their forums, including waiting half a minute (and longer) between taking the old battery out and putting the new one in, but nothing worked. As the batteries came in a two-pack, I tried the second one too. Nothing, so I figured the strap was broken. I usually keep all my receipts, but, of course, when I got home, I couldn't find this one. So, no warranty. Therefore, I bought a new, less fancy strap.
A couple of weeks later, I ordered some batteries online and I figured I could use some CR 2032's, so I ordered ten of those, but this time, from a different brand – GP. I tried them in my 'old' HRM-run strap and guess what, it worked again. I talked to someone at Garmin and he said 'Oh, yes, Duracell's do that some times.' Nice... it would have saved me a lot of money knowing that before investing in another strap.
Moral of the story: try different brands of batteries. If you use a Garmin HRM-run chest strap, try other brands than Duracell.