DETROIT – General Motors Corp.’s OnStar telematics service says up to 500,000 customers will lose service in 2008 due to a major infrastructure switch from analog to digital networks.

But a top GM executive says the auto maker won’t leave customers in the lurch.

“We’re not going to walk away from those 500,000 loyal OnStar users,” Troy Clarke, President-GM North America, tells Ward’s at a media event here, adding he expects an announcement from OnStar management soon.

OnStar anticipates 12.5% of its 4 million subscribers will be dropped in February 2008.

The expected outage follows a 2002 rule by the Federal Communications Commission that allows cell-phone service providers to switch off their analog networks beginning in February 2008. OnStar partners, such as Verizon Wireless, are expected to do just that.

OnStar relies on both digital and analog networks to connect with its subscribers. Once the analog network is shut down, car buyers who purchased an OnStar-equipped vehicle before 2002, as well as owners of some ’02-’04 models, will find their OnStar links severed.

A recent story in The New York Times estimates about 2 million subscribers will lose service. But OnStar disputes the figure, saying it will be able to convert hundreds of thousands of vehicles currently using analog-based systems to digital.

Bill Ball, OnStar vice president for public policy, says OnStar is coordinating with dealerships to install the necessary hardware and will be contacting customers. OnStar will update their system for a $15 fee and offer a 1-year subscription at regular rates.

“Hopefully, we’ll be able to make a smooth transition for these customers,” Ball tells Ward’s.

GM’s OnStar subsidiary was launched in 1996 on an analog network run by Verizon Wireless but was caught between two infrastructure technologies. Ball says the FCC’s decision came down in September 2002, at the start of the ’03 model year.

“At the time the FCC made its decision, there was not a solution for delivering telematics on digital cellular technology,” he says.

OnStar began adding its dual analog/digital technology in ’04 vehicles and increased distribution of the system in ’05 models. Now, most ’06 and all ’07 OnStar-equipped vehicles have digital systems, Ball says.

OnStar already has informed impacted customers through its magazine and website. However, Ball says some customers still may be surprised to find their roadside assistance and emergency services cut.