2 months back, I opened the hrm-pro to replace the battery. hrm-pro indicated that the battery was not good anymore. After replacing everything was fine again. The first battery lasted for 11 months. I will try to remove the battery this evening to see if I can get the hrm-pro revived. It will record a heart rate that doesn't change with exercise intensity (eg HR stays at 83bpm), or lose contact or give excessively high readings. I have tried all recommended suggestions, wetting the strap, placing strap on in advance of a ride, replacing battery, tried pairing it to hubbie's Garmin but after unpairing and attempting to re Hrm Pro and Run are unusable after first change of factory battery cause the sudden discharging of all new batteries andrewc71 over 2 years ago Not washing the strap often enough. Not washing your heart rate monitor enough could cause what’s known as acne mechanica from the constant rubbing against your skin—but keeping it clean isn I’ve changed the battery to my Suunto HRM many times. Usually I know the battery is dying by either not connecting at all or constant (long) drop outs during an activity. Other than that the Suunto HRM works without issue…when the battery is new. Sure the HRM pro loses its signal every once in a while, but it’s nothing crazy. Remove the battery door. Gently pull up the battery tab , and remove the battery from the battery door. NOTE: You can also use a magnet to remove the battery. Wait 30 seconds. Insert the new battery in the door with the negative side facing up. Replace the battery door. The battery door must be flush with the heart rate monitor module. I received a message that the battery of my Running Dynamics Pod was low, so I replaced it with a brand new battery following the instructies provided by Garmin. Unfortunately, the pod is not recognized anymore by my watch. I tried deleting the pod from my watch (FR735XT) and searching for it again (while walking around with it), but no luck. Sounds like the battery is weak and you're getting cadance lock. Clean up the internals and replace the battery then reassess. You can also try removing its connection from your watch then replace the battery and add it again after. r/Garmin. wkt6.