lights dim on 2001 grand caravan when hitting brake

[jtfrock]

I have a 2001 grnd caravan sport with approx 143000 miles. Installed new battery 3 to 4 years ago. I have noticed when driving at night with the lights on, they will dim at when stopping at a stop sign but will come back up to full strengh within a 1 second. Also when starting at times, the battery light will come on for a couple of seconds and then go off. Any ideas if this is a battery or alternator issue? Also, sometimes a bearing whine on start.
thanks
jason

[mfahey]

Any number of places can test your electrical system for you to take the guess work out of things but the whine would seem to point to an alternator.

[Vistal]

id have the battery and ALT tested . I just replaced the alt about 2 years agao and still had the problem.I replaced the battery like 2 months agao and have not seen the problem come back.

[Rick99]

I'd suspect the battery first. I just had to replace the battery in our van with 3 1/2 years on it, so that's pretty much what you can expect to get. At your mileage a bad alternator wouldn't be out of the question, but since you're about near the end of the battery's life anyway I'd just replace that first and see if it does it. Actually, as a first measure, you may want to check if your terminals are corroded. If so try cleaning them up.