My Brake Light and Battary light is on!!

[Andres322]

while i start my car the both light will come on...i have to drive few km... then the light will disapper... it will comes on sometime.... i check my brake fluid it's full...please help... i have infiniti i30t 2001

[Q451990]

The brake light typically doubles as a low voltage indicator on most Nissan products... probably a bad alternator or if you're lucky just a bad battery.

Good luck!

Heath

[Skibane]

Yep, that sounds like the real problem.

If you have a digital voltmeter (and you should, since they're widely available for less than 10 bucks!), you can measure the voltage across the battery terminals.

With the engine idling and no major electrical accessories turned on, it should measure at least 13.8 volts DC. If it's lower than that, your alternator isn't doing an adequate job of keeping the battery charged - and probably needs replacing.

Note: There are exactly two kinds of replacement alternators available:

1. The genuine Nissan factory part, and2. Varying degrees of Crap.

[k2tone]

Not sure this will help but I've seen the two lights come on together. However, my car had been screaming, and I knew I had a pulley issue. I had driven through a pretty large puddle, stopped for gas, and when I turned the car back on, I had the two lights on (with a terrible noise - like a watery bubbly sound). I drove about a mile and the lower engine pulley dropped out - sounded much better and I was able to drive after (my destination was only a minute away). The mechanic fixed it and it immediately dropped out again during test drive. The a/c compressor was frozen and causing the belts to tense up which pushed the pulley out. Sure hope this isn't your issue too. (Considering, after this expensive repair, my SES light is on now.)

[loystock]

It's an indication of a 'dying' alternator - internal diodes are failing. Once confirmed, you can take it out and have it repaired at an electrical shop or buy a new one. I agree with Skibane, go for OEM if you're going to buy one. I learned it the hard way. Since it takes at least 3 days to get parts from Infiniti of Scottsdale and my daughter needs her car for daily commute, I bought the alternator from Kragen. Bad decision - the first two replacements failed within several weeks. Fortunately, in both cases, the car was able to limp home. The replacements were free (warranty) but doing 3 alternator R&Rs in a row is no fun.

Rod