This ain't New Joisey...
Things like On Star, and Lo Jack DO NOT WORK in most of the country. Some of the DO NOT WORK is due to incomplete infrastructure, other part of the DO NOT WORK is due to personnel.
EXAMPLE: Twenty seven tow companies in a 75 mile radius. Eighteen may not wish to write up a FACTURA which is a registered sales document with Hacienda, Mexico's tax department. Four companies may have broken trucks, like the tow service across the street here. The remainder may not have a good connection or relationship with the Green Angels.
Outside of this town 3KM there are ZERO BARS on all phone services. It stays that way for 68 miles. Then phone service for 5KM then zero for 73 KM, then 4 more KM with phone then Three HUNDRED KILOMETERS with no service.
Just like AIR EVAC service. SEVENTEEN HOURS after a phone call the patient is wheeled into a USA emergency room.
Just realize what it is you are and are not getting with these gizmos. I live down here 24/7 365 and outside of cities it is a whole different world.