I have a 2004 Mazda 3, automatic, I've had it for five years. No problems until 2mos after I changed the battery. The dealership has checked the battery connection and the alternator and they are fine.Here's the problem, inside lights shut off and then turned back on. I have to reset the radio/clock. It would keep for a few minute, but if the car is off 15 min or longer everthing has to be reset again. This past Friday the radio did not come on and the clock did not come on as well as my navigation system. The trip mileage reset itself. None of the interior lights came on. It appears there is no power going to the radio and clock. Neither have come back on. My key fob to lock the doors and that no longer works. In addition, there are no inside lights at all, such as my map lights. The lights that are supposed to come on when the headlights are on are not turning on. Finally, each time the car is turned on, the gas gauge goes crazy for about 10 seconds and then stabilizes, which it had previously stabilized itself right away, and the trip mileage resets itself every time you turn the car on. I have checked all the fuses and none are blown. We have also checked the battery terminals and they are fine.

 

you might have a short, somewhere, a bad alternator, or (hopefully) just loose battery terminals

 

Here is a post that offers one possiblity:


One solution to intermittent or permanent headlight failure can be found on the post by SEVARGMT on 9-29-2010.

It seems to lie in corrosion of the wiring system connectors in the PJB, a specific wire connection junction box located under the passenger side glove compartment box.

It seems possible to repair the corroded pin connector but it is probably best to have the dealer replace the entire PJB to avoid repeats of this problem, as it is a dangerous situation when headlights go out at night, like mine did.

Brilliant problem solving by SEVARGMT and DJS2571. They also developed a convincing theory of what causes this problem: the air conditioning line located above this box creates condensation, which then drips down on the wire connectors and causes them to corrode, causing an electrical fault. They suggest a plastic drip sheet to avoid future corrosion.

Wouldn't it be great if Mazda assigned an engineer to read the forums for problems with their cars and prepare posts with solutions? It is plainly obvious that a problem is very common when you look at the number of "views" listed for certain topics, such the headlights (many thousands of owners have headlight failure problems). Mazda should have issued a bulletin or a recall since the corroding PJB is clearly a safety problem. This looks like a design/engineering flaw. Every electrician and plumber knows to never put moisture sources above electrical boxes. Shame on them.