I have no experience with your Garmin model, but the X96's with dead calendar batteries can be brought on line fairly quickly by turning the GPS on; when the page comes up where it is trying to locate satellites, hit the "menu" button; scroll down to the bottom line which on the X96's reads "Auto Locate"; hit "enter" then hit "automatic"; It should "find itself relatively quickly.
No guarantee on your unit, but it works on the X96's. Hope this works for you!!!!!!

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LAUS DEO
Mannan J.Thomason, MSGT. USAF (RET)
VAF788
"Bucket List" checkoff in progress!