electrical problem
 

I took my car to get its 8,000km checkup, and when I was in there I asked them to take a look at a problem I'm having.
In the evening when I start my car, turn my headlights on, have the radio on, and have the heater blowing my dash dims and brightens alot. They said they looked into it and there is a voltage drop happening. They also sent off a report to Mazda about this because they have not seen this type of problem in the Protege before.
I was just wondering if anyone else had this problem and what got fixed to stop the drain.

I do...and don't even have to have the heater fan on....but then I KNOW what is causing the drain...its my AMP that is added into the audio system....you can watch the lights slightly dim and rebrighten every time the sub hits real hard.. :{D common thing when you upgrade the audio system and add amps.....can be solved by adding caps to your power supply protion of the amp.

My problem is that it is completely stock.
I've had cars do the same thing when I put alot of extra stuff in the car, but never when its stock.

lights dimming
 

you might look into the alt have seen a some go bad, also check the grounds on car. when you look at alt you will have to scope check it . and look at the scope pattern. my car does the same thing with stock radio and put on hyper ground which worked

Re: lights dimming
 

I have this same thing happen to me. I also have an amp installed, and put in a power wire from the battery to the amp. Obsviously, I dont think its due to the sound system, as it did it before, and I have had no amp connected with the power wire circuit breaker open for about a month now, and it still does it. Sometimes it does it though, because the idle tends to dip down at times when it's idling (No AC). Could a bad alt be causing a dip in idle RPM?

Do you think a Mazda dealer would deny warranty on a bad alternator for me having a sound system?