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Need some advice...Mazda6...battery/alternator issues on hills!

Recently I noticed that the front headlights of my 2005 Mazda6 were dim. Since the turn signals and brights were still working properly, I assumed that my problem was related to my battery (which was on the older side) and took the car to a local shop to have it replaced. The mechanic who looked at my car said that the stickers on my battery indicate that it was replaced in July of 2009 and showed me that the alternator was putting out a charge below 14V and told me I needed a new alternator. He replaced the alternator and when I asked him to turn on the lights, they were still not working. He replaced the bulbs on a few of them and appeared to be having difficulty removing the light to replace the last one, even with the help of his assistant who he called over halfway through these attempts. At this point, I was becoming suspicious of the mechanic working on my car (this was the first time I had been to this shop), so I asked that he stop working on it, I paid for the work done and I left.

The next day, the battery light on my car dashboard came on. As it turns out the new alternator was faulty (this was verified by the dealer, who looked at my car after the alternator was first replaced because of my suspicision) and I took the car back to the shop who installed the alternator asking that they fix the battery light. They correctly concluded that my alternator was faulty, replaced it and gave me the car back.

The following day driving around my neighborhood, my check engine light and various other lights on my dashboard came on whenever I stopped on an incline. Eventually, at all these stops it seems like the car lost all power (almost like the battery died) and the only way I can get moving again when traffic started was to turn off the car and turn it back on again. This is a problem for me because my neighborhood is fairly hilly and the traffic is largely stop and go (many stoplights, residential area where I’m very likely to get stopped behind a school bus or city bus).

Any ideas what is the problem here…and…where do you suggest that I get it fixed? (The local shop – closer to my house, but suspect quality… or the dealer – further from my house, but less hills to get there)?

Thanks for any advise you can give!

It sounds like there is problem within the main power distribution panel area under the hood. If the battery connections haven’t been cleaned start with that. Then make sure that the power wire from the battery to the main panel under the hood is making solid connection. It would help to have a voltmeter to check things with. You can also try tapping on suspected trouble areas with a screwdriver handle to see if the trouble shows up that way. It may also help to clean the chassis ground connections.

There may be a seperate relay for the low beams and the contacts are causing a voltage drop to the lights. The DLR circuit may not be cutting out when the lights are on.

You need to find a mechanic who can do tests and troubleshoot, not just blindly change parts.
Cougar made some good suggestions, but over the internets all we can do is guess.
Click on “mechanics files” at the top of this page to find a good shop.