I recently replaced the battery and alternator on my 98 Diamante. No problems until a a few weeks later. After driving it for 30 minutes or so, the low battery light and the brake light on the dash come on. I have had the battery and the alternator checked and both showed no problems. The car has never failed to start and the battery seems to be charging as it should. I've put my battery charger on it and the needle is almost on "0" and in a couple of minutes, it shows to be fully charged. Any ideas?

 

its almost assuredly the alternator. Ill be you DIDNT use a mitsu alternator, but rather a NAPA or carquest rebuilt unit, correct?
Theyre all junk. The mitsu one is super expensive, but is actually built with mitsu componants. The aftermarket ones will be rebuilt often with chinese sourced junk.

 

Yea those rebuilt ones are TOTAL crap, my friend went through 3 in a row for his Ford truck other week from Advance Auto. A few college auto shops wont let students use ones from AutoZone or Advance Auto they are so shaddy. I would make the place test the new one before you leave with it, I know Advance Auto tests them on the spot. I dunno what to say about the brake light being on, the switch might have gone bad that tells the light to go off when the brake is off.

 

I have the same lights that come on. I had my alternator replaced with and OEM one I bought from carquest because the origional one died. It seemed to fix the problem but two weeks later the lights came back on. Last night the lights were on andeventually the car died and I couldn't start it because of low voltage. It sat for about 30 minutes and there was enough build up to start it and I drove it home and the lights stayed off. I started it this morning and the lights stayed off my entire 40 minute drive to work. I am wondering if there is a switch or component that is getting stuck that allows the current from the alternator to get to the battery.

I also don't get why the break light comes on. They don't seem to have any thing in common.

 

I am also having the same problem with the original alternator on my '98. The Batt/Brake light comes on mostly during idle. I can bump the accelerator and it will go out. This problem was compounded with the fact that my Starter was acting up and eventually stopped working.

I am also curious why the Brake light also comes on with the battery light.

 

I already made a new post about my issue, but it is almost the same as ya'lls problem. Have any of you guys figured out if there is something between the alt and the battery to stop it from charging. I didn't use a Mitsu alternator either I bought an Autozone one, problem is they won't let me exchange for a new one as long as the one I have tests as "good" I paid $180 for it only two months ago! Now my wifes truck is sitting in the driveway! It's a 2wd 01 Montero sport with the 3.0.

 

people, you get what you pay for.
theres a reason those aftermarket crap alternators are so cheap.


buy good ones. Or buy used ones, which are definitely better than the aftermarket rebuilds.

 

Funny the same exact thing happened 2 days ago with the lights. Its was later determined that my alt. was putting to much power out. I orderd a rebuilt alt. which I have to pick tomorrow. I just finished removing the old one. 2 1/2 hours( I had no clue how to get the alt out) if i would of known whould of taken under a hour. I'll let u know how it goes tomorrow. Are there any topics fr alt removal?

 

There may be a topic somewhere, but I have had mine on and off a total of about 8 times so I can do it in a matter of minutes now.

My steps are: Disconnect the negative battery terminal. Then from underneath loosen the screw in the center of the pulley to relieve the pressure it puts on the adjuster screw. Then loosen the adjuster screw to relieve the tension on the belt. Then going in through the wheel well undo the plastic apron cover and undo the battery wire to the back of the alt then unplug the other two wires. Then I get back under and take out the small mounting bolt on the bottom of the alt. Then from the top take out the top mounting bolt. Next back over to the wheel well to reach and grab the alt and pull it out through the wheel well. You don't have to remove the front wheel, I just turn it some to get the front out of the way some.

Good luck. I hope that helps someone.

After trying and trying to find an issue for a week I ended up having to take mine in, and sure enough it was the alternator. The mechanic told me to tell a certain person at autozone that the alt was bad and to exchange it. The dude at autozone did with no problem and I had it running again. Now it's in the shop for an oil leak from the valve covers, new plugs and wires, and timing belt. I should be able to go another 100,000 miles after all this. I hope.

 

You dont even want to know how I got mine out........I pulled it out from the top Took the fan out, alt mount and so on.....But it did turn out to be the alt. I didnt put the plastic washer that came with the remanufactered alt and I kept poping the 120 fuse when reconnecting the battery.Not a good day. But all is well for now. LIGHTS OFF