Blaze syncs, but won't stay paired with phone while running

[JimKohli]

I've had my trusty Blaze for a few years.  Some time in the last month, it started this thing where I would tell it I'm going for a run, it would search & find the phone (for GPS), and wait for me to press Go, but the bluetooth signal bars (see picture) indicate one red bar. That's it.  It used to have 3 or 4 solid green bars.  I have no idea why the Blaze indicates bad signal strength from a phone that's 1 foot away from it.

If the Blaze connects, it doesn't stay connected to the Android smartphone (Blaze classic) so I don't get route information and the other trip measurements are suspect.

I've done most of the usual kinds of things - forget/re-pair, uninstall/reinstall the app

[JimKohli]

Okay, apparently we can't post pictures here.  You'll have to imagine the Blaze doing that "Connecting to phone..." thing,

followed by the display with the little cellphone icon in the upper left with some signal bars.  In this case the shortest bar is red and the other bars are not lit up.  "Let's Go!" is displayed and there's a chevron button in the lower right corner.

[JimKohli · Accepted solution]

The problem turned out to be that the Fitbit app somehow became switched so that it only had access to Location when the app was active.  Changing that to Location access on all the time fixed the problem.