Turn-by-turn directions are given by spoken voice prompts with text-to-speech pronunciation of street names. Voice prompts, like hands-free calls, are heard through the unit's internal speaker. Even at its loudest, the internal speaker is only about as loud as your average portable navigation device. So, if your vehicle generates a lot of road noise, like our Explorer, or you're also playing music though the vehicle's speakers, you'll have to listen carefully so you don't miss a turn. In the event that you do miss a turn, the FMV has a limited capability to reroute your trip, but if you get too far off course you may have to manually reinitiate routing.
Knowing where to go without the visual feedback from a map took a lot of getting used to, but it wasn't so difficult that we couldn't manage. On one or two occasions, after missing a turn, we were instructed to return to the route, which was harder than it sounded without a map. In those cases, we elected to just restart the trip with a call to OnStar.
The third button is for Emergency services. After tapping it, you can summon medical, fire, or police assistance, report an accident, or, if you're a good Samaritan, summon help for another motorist. If you need nonemergency help--for example, a tire changed or a tow truck called--the standard OnStar concierge can dispatch Roadside Assistance. Automatic Crash Response summons emergency personnel if the system detects an accident and the user is unresponsive to a call from an OnStar operator. For obvious reasons, we did not test this functionality.
Core OnStar functions that are not supported by the FMV include Vehicle Diagnostics and Remote Door Unlock. Also, although the system is able to track a vehicle reported as stolen, FMV is unable to stop the car.
Many are no doubt wondering why we didn't have the FMV unit installed in our regular test car. We were told that our 2007 Chevrolet Aveo was incompatible with the OnStar FMV, which was a bit of a black mark on the universality of the FMV, but, to be fair, we've experienced issues in the past with the Aveo's compatibility with certain OBD devices, so we'll chalk this up to a "car issue" and not an "FMV issue." You can check your vehicle's compatibility before you buy on OnStar's Web site.
The OnStar FMV retails for $299 and requires professional installation, so go ahead and figure an extra $100 for labor. Owners will also need to subscribe to the OnStar service, which runs $18.95 per month or $199 for a year. At that price, the FMV competes directly with the newest batch of connected portable navigation devices, which do a better job of guiding drivers from point A to B for people who like to search for their own points of interest. But if you like the idea of having a real person on tap to help you pick destinations and a safety net of roadside assistance and emergency services always available, OnStar FMV may be worth consideration.