Here in California, we don't have the option of having batteries and alternators tested at auto parts stores. I tried Googling for the reason why, but the closest I got was that it has something to do with some California law that bans non-certified technicians from doing repairs (even for free), which apparently includes even simple diagnostic tests. Your choices here are pay a mechanic, or learn to test batteries and alternators on your own. Gee, thanks California.
I'd be willing to bet that being "certified" to perform those repairs in California requires little more than a hefty payment to the state for an official "license to repair" (which must be renewed annually of course).
I wouldn't take that bet. You're probably right about that. The weird thing is, trying to Google why California bans auto parts stores from performing free diagnostic tests is like trying to use Google to figure out who
really killed Kennedy, or what's going on at Area 51. In this case, all I can find is lots of vague references on car forums to "something" happening in 2008 that caused all the auto parts stores to stop offering those services in California. Nobody seems to know what that "something" was. Nobody on any of those forum threads has managed to find any smoking gun in California law. Nor any news articles about it, etc.
Lots of speculation though. Some of the theories that people have come up with are:
* That performing diagnostics is tantamount to repair, and only certified repair shops can do that. However, no news stories about any auto stores getting fined or anything.
* That mechanics complained they were losing work due to the free diagnostics offered by auto parts stores
* That auto parts stores using untrained personnel to run diagnostics were steering consumers toward incorrect and/or unnecessary repairs
* That auto parts stores had been successfully sued in California courts by consumers for giving erroneous test results (i.e, you said my alternator was bad and it wasn't)
By the way, I misspoke. You can still get a battery tested and even charged, apparently. But alternator testing, as well as OBD2 code scanning, etc, are all banned. Basically anything that could be construed as repair. Also, we're apparently not the only state that has this ban. Check any of the major U.S. auto parts chains' websites, and they all say "Except in California and Hawaii, where it is prohibited by law."
As annoying as it is that California thinks I'm too dumb to take some pimply faced AutoZone employee's diagnosis of my alternator with an appropriately sized grain of salt, the real annoying part is that it's all shrouded in secrecy. I'm sure I could consult an attorney and have him point out the specific sections of law, and explain how that means parts stores aren't allowed to diagnose my alternator. But that information should be freely and easily accessible to California residents, and it's not.
But all that being said, yeah, it's just as well that I have my own code scanner, and have learned how to do my own diagnostics.