The issue is intermittent. Sometimes when I turn on the ignition, the DIC does not light up. There is a delay of two to three seconds and then everything on the DIC works and the Service Vehicle Soon (SVS) light comes on. The HVAC console will not work during all of this. Rear defroster and AC button do not work. Day-Time running lights, head lights, high beams, radio, windshield wipers all work. I do feel hot air coming through the vents, but not fan driven. Replaced ignition and computer in July 2011 with GM dealer flashing the computer. New battery December 2012. I have had it in to a mechanic but they were not able to get a code from the computer re: SVS light. Low coolant light now coming on in the AM (cold mornings), but turning off. Checked coolant and it is full.
Are you sure it wasn’t the service engine light?
Service Vehicle Soon sounds like a maintenance is due.