Yesterday I noticed that my brake and battery light are staying on at the same time while I am driving. It flickered a couple times and even went off once, but when I stopped and started again, the lights stayed on.

What does this mean? Can a place like AutoZone or PepBoys check this without me having to take it to an electrical place and having all sorts of diagnostic tests run?:uhoh:

Any help would be greatly appreciated! :)

Check for corroded or loose battery connections, but most likely your alternator is dying. Replace with a bosch or OEM one.

Don't be surprised if both your battery and alternator are taking a dive; everytime I've lost one, I've lost the other within a day or so.

Definitely use an OEM, Bosch or Napa alternator - do NOT use any other reman alt, or you'll be wasting your money and time.

For the battery, I have an Interstate with the highest CCA available, that mated with a Bosch alternator has been great for almost 4yrs now.

Also, these trucks are famous for giving off weird symptoms when the volts are low, so don't be surprised if you seem to start getting electrical gremlin issues, it's merely the truck's reaction to low voltage. This includes auto tranny shifting issues, radio & hvac controls not working, a series of idiot lights on the dash, etc.

Battery/brake light is the Isuzu way of telling you that your battery, alternator, or both, are giving up the ghost. You'll find other idiot lights may or may not come on, i.e. 4x4, abs, check transmission, etc.

Classic alternator post.

I'll second the need for a good battery when installing the new alternator. Have the existing one tested and charged, if needed, or install a good battery. You don't want your new alternator laboring to charge a lousy battery.