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'99 Mits. Diamante with brake and battery indicators on

My '99 Diamante has the brake and battery indicators simultaneously coming on. Strangely, they usually disappear when I accelerate or keep steady pressure on the gas pedal and come on during deceleration. I had a new battery fume/smoke and spew battery acid and had to be replaced. Then, I had the battery terminal replaced after it broe down a second time. I thought these two actions would solve the indicator warning light issue, but apparently not. Now, I am concerned that either there is a short causing the indicators to come on, or worse, an indication of a problem that will lead to the issues we have already experienced. Any help/advice/direction is appreciated.

When two normally separate electrical circuits have problems together I suspect ground connections.

There’s probably a ground line in the wiring harness that goes from engine compartment to the dash.
Check the condition of that under hood connection.
Also the ground wire from motor to the body.

Your alternator is failing and is putting out inconsistent voltage.
Because of the way that the warning lights for the brake and the charging system are wired in the same circuit, the problem with your alternator is causing the brake warning light to light up also.

Incidentally, unless you want to replace your battery again, you need to replace the alternator right away. Truthfully, if I were you, I would do it today before that battery explodes or you have other serious electrical system problems.

yeah, either you have a failing voltage regulator (a part of the alternator in most modern cars) or a bad connection (probably ground) at the battery. take it to a battery shop or and have it checked out by an auto electric shop.

Thank you all for your prompt replies. I feel I have narrowed down the direction to go in and will check the ground wire first, then the alternator if it doesn’t appear to be the ground wire. I’m afraid to ask how much an alternator with labor would cost. I have taken it by Autozone three times to have alternator/battery/starter checked. The alternator has tested fine each time. Do you suppose the test Autozone uses isn’t comprehensive enough?