My battery light came on intermittently. Now it happens at startup, and stays on until i rev past 3k. it will be gone until i hit traffic and idle a lot, or the next trip.
2 different places (O’rileys and Advance Auto) checked and alternator and battery are fine. I have tried cleaning the contacts, swapping batteries, and replacing the battery fuse with no luck. Suggestions?
Check the serpentine belt and its tensioners. It may be slipping.
How did they check the alternator? With a voltmeter while it was in the car? Or did you remove it and take the alternator in? If they did a check in the car, you really need to check the voltage when the battery light occurs so you can see what’s going on. You can buy one of these and you get a phone charger to boot:
https://www.amazon.com/Car-Charger-Smartphone-Temperature-Fahrenheit/dp/B00SWGWILI/ref=sr_1_4?ie=UTF8&qid=1534520562&sr=8-4&keywords=voltmeter+cigarette+lighter&dpID=41RGVeQPDsL&preST=SY300_QL70&dpSrc=srch
They checked it in the car. Ill test the serpentine belt then look into that tool.
Do you have an oil leak that has soaked the serpentine belt with oil.
If so, the belt will slip on the alternator pulley and not turn the alternator fast enough.
Or as @Mustangman mentioned, the tensioner may be weak.
Yosemite
Thanks yosemite! Ill check the belt for oil too. I just picked up the rachet extension i need to check the pullys today so i should know soon.
Need an alternator when u rev it higher it spins faster so it’s sble to charge the battery but when at lower rpms it cannot because it’s failing
Just cuz it tested fine doesn’t mean it’s not intermittent I just had a customer with a 09 Honda Pilot same issue and tested fine but light would come every now and then. Then one day it came on and failed. Also check the battery cables and the ground on the battery negative cable