When we talk about battery problems, we almost automatically conjure up images of slow-cranking engines or the disheartening view of all the indicator lights going from dim to dark the instant you try to start the car. Granted, batteries can be stealthy saboteurs, operating perfectly until they hit us with the silent treatment. Determined not to communicate with the starter anymore and equally resolved to pay no attention to the alternator, they make a show of force (usually at the most inconvenient time) that they are totally independent of the rest of the vehicle. This obvious defection from the team immediately warrants a replacement with another battery that's all too happy for the opportunity. Sometimes, though, we aren't lucky enough to have a blatant battery insurrection.

While at the Corvette Clinic, a '98 came in with what seemed to be an HVAC problem. There was no control of defrost, heat, or vent positions inside the car. The Clinic did some diagnostic sleuthing and found that the system did not have a supply of vacuum to operate the valves. What do the vacuum system and electrical system have in common on a C5? Follow along and we'll show you.