This is a possible fix for your Garmin Vector 3 power meter pedals.
After replacing the batteries on Garmin Vector 3S pedals, you are no longer able to connect the pedals to your GPS device.
**Update** Garmin has began providing free replacement battery casing that should resolve this issue.
A POSSIBLE SOLUTION:
When taking off the battery cap with a 4 mm hex key, you will also pull out the battery casing. This cap and battery casing has a key flaw- when you take out the batteries, there are two black rubber squares made of insulation tape similar to electrical tape that are 5mm x 5mm squares. When you take out your original batteries, it is easy to accidentally remove these pieces of tape as well. If you see that your cap mechanism is missing the black squares that cover these pieces, simply cut square of similar size (5 x 5mm or larger), to replace them.
Not sure if the issue was fixed by stabilizing the batteries in the casing, or it covering those metal pieces is vital for battery operation. Either way - it worked.
Another issue that people have encountered is power drops with the Garmin Vector 3 pedals. Our experience shows that battery connection stabilization is a potential remedy for this problem.
Hack 1: Follow the above steps to secure the batteries within the battery sleeve, which should keep the batteries in more constant contact.
Hack 2: Insert a thin piece of plastic or cork under the "H" piece of the positive end of the pedal where the battery contacts the electronics to fix a faulty connection between the node and the battery.
Hack 3: DO NOT over tighten the battery cap with your 4 mm hex key. Tightening the battery cap can break the yellow ring that sits above the threads on the cap. There should be extra rings included with the purchase of the pedals. To avoid breaking this ring, stop wrenching as soon as you feel resistance on the cap. Snug it up, but be wary of over tightening (less than 2 nm)