Headlights dim or go out when brakes applied
 

My granddaughter has a 2000 Toyota Camry. At times when the brakes are applied at night the lights will dim or go out. The radio will also dim and quit. The next morning the battery will be dead. The alternator was tested as good at Advance and a new battery was installed. I've just become involved with trying to find a fix. I'm thinking a bad ground but one question I have is which ground and how would I find out where they are all at or would it be just one specific ground? I know the alternator and or the regulator can be bad even if it test good but I don't want to just start throwing parts at the problem. The problem is intermittent. Any help will be greatly appreciated.

Do the lights also dim with heater blower usage or other heavy loads?

Check voltage between battery cables with engine running at approx 2000 RPM. Voltage should be approx 13.5-15.1 volts. There are volt meters/indicators that plug into the cigarete outlet.

Check battery cable connections. Battery cable ground connection at chassis.

If an alt issues and original unit. The alt has easily replaced brushes and regulators can be purchased on line.

Thanks toyomoho. I have failed to mention that I don't have the car at my place yet so I don't know the answers to some questions yet such as do other heavy loads cause the same problem so I'll have to wait and do some more testing when the car gets to me. I'm going only on second hand info of sorts right now. When I find out more info I'll repost here with what I find.

FIXED!! I finally got the car and did a voltage drop test on the alt. I tested it by starting the car and turning on everything electrical on the car and making the test that way. The ground side failed the test. A new battery and battery terminal connector for the ground side had been installed BUT the ground cable itself was corroded! I actually installed a new, from the salvage yard, ground cable and did away with the aftermarket connector. The cable cost $5 bucks. The car performs great and even starts better! Thanks for the help.

Great job!

Thanks for posting back with your efforts.