I have a garmin hrm3-ss ( that came with the garmin 520 bundle ) that I can't get to read.

I've replaced the battery, did the trick where you connect the terminals to reset the unit, and at best I can occasionally get the unit to connect to my 520 ( all other sensors work and connect fine ) but still can't get a reading.

I've tried new batteries, new straps, and seemingly everything but the unit itself.

Is there anything I could be missing or are they just generally crap?

( I bought it at performance bikes, so i'm going to contact them to see if I can get an exchange as its less than a year old )