ok so i just recently changed my battery and alternator from autozone.. but now for some reason when im driving or stopped my battery light keeps blinking... if i hit the gas hard enough or press the brake it stops blinking but when i let go it starts blinking again.. and also if im stopped i can even hear i guess its the alternator everytime it blinks it gets a little loud and quiet loud and quiet pretty fast every time it blinks u can actually hear it its a 92 civic hatchback

 

Get it tested. Check the grounds possibly.

 

Make sure that the alternator mounting bolts and belt are tight. If they're fine, have the alternator tested, as Marc suggested.

 

so i got my battery n alternator tested n everything is perfect when i drive sometimes it starts blinking but if i press the gas or brake it stops

 

Are the belts tightened properly?

 

yeah that's most likely a not properly tightened belt.

 

did you have it tested to see how many amps it puts out? a altenator can put out 14 volts, but if its putting out 2 amps then its useless.

 

Well I can tell you why the light goes off when you press the brake...

The Electronic Load Detector (ELD) in the engine bay fuse box sees the demand for increased amperage when you press the brake pedal turning on the brake lights. The ELD then sends a signal to the ECU, which tells the alternator to go into "full" charge mode. As soon as you let off the brakes again, and all other criteria are met, the ECU then switches alternator back to "low" charge mode to save fuel. Now if your alternator is not putting out enough amperage in low charge mode at idle, then your charge system warning light will come on. Of course if you rev it a little bit, or switch on an accessory that requires more amps, the light will go off again when the alt puts out more juice.

What you need to do is bring that alternator back and ask for another one anyways. Even though it's testing fine (under load of course), it's not putting out enough amps in the low-charge mode at idle to keep your battery light off. I know this because I had the same problem for something like 5 years. My cruddy re-manufactured alternator I bought from Checker finally died and all my problems were solved with a replacement form Autozone. You'll just have to keep trying till you get a good one.

Here is my thread on the subject (note the post dates): https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/please-help-%22charge-system-warning-light%22-1590576/

BTW: I even had one reman alternator where the light would come on at high-rpm only. My mechanic at the time told me it was the brushes inside that were bouncing off an out-of-round commutator. It means they didn't cut the comm when they rebuilt it. A major oversight when installing new brushes in anything! These types of problems are very common in cheap remaned parts.

 

Check your grounds for corrosion and rust. If nothing else, it's just good practice when having electrical issues.

Check the power at the battery. Amps and volts to see if it's within spec. Then check with the car running idling, then hold the throttle up a little and check.

Or just say the alternator is junk and get a different one. They can test fine and be junk still. My brother went through like 5 on his Yugo since it's a rare car...

 

It's the alternator. Return and get another.

 

Most likely^

But also check for a loose alternator belt or loose alternator mounting bolts.