Hey guys, my car pooped on me yesterday so I went out and got a new alternator and battery. I made sure to install them both properly and after the initial jump due to my battery being drained from the bad alternator all was well. However my check battery light is still on. I took it to auto zone and they tested both the battery and alternator and they said it’s working like it’s supposed to. I took my car out on the highway and when I reach higher speeds the light will turn off. After some time slowed down or idled the light will turn back on. I’ve checked all of the connections. I’ve also disconnected the negative terminal for a bit to see if that would reset the warning light. Maybe it’s the wiring? I’m unsure and would like you guys to give me some feedback. Thanks!

Update: the mechanic told me it was a wiring harness that was worn out so I got that replaced and the battery light is off for good. Thanks for the help guys

Yep. I’m going to bring it to a shop tomorrow so they can check the codes and give it to me straight. Thanks

You can buy one of those system testers for under $20 even at Walmart. Plug it in to the accessory port and will tell you the battery voltage at rest, and then while you are driving. Complete with red, yellow, and green lights for quick reference. Should be over 14 when driving. I have one in each car just to check once in a while since they don’t have volt meters in most cars anymore.

Good for you. One bit of advice, suggest to not run engine w/battery disconnected. Battery acts like big capacitor, filtering out alternator’s voltage spikes. Potential damage to sensitive car electronics.

Worn out wire harness. Inconceivable.

[image] Kaioutlaw1: Update: the mechanic told me it was a wiring harness that was worn out so I got that replaced and the battery light is off for good. Thanks for the help guys The way I read this is a wire was grounded where it shouldn’t have been and caused the problem. I had a '99 Monte Carlo that needed an alternator. The new one crapped out too. I looked closely and found the positive battery cable had been rubbing on something (Since the car was new) and the insulation finally wore through. As I moved the cable I actually saw sparks! After I fixed the cable and another new alternator the problem was gone.

[image] Kaioutlaw1: that Dealing with this SAME EXACT issue for over a year now… but with 2015 Infiniti Q50 3.7 Premium. New alternator, battery, belt is fine, tensioners are fine. I feel like the issue has to be with the wiring, but the Dealership mechanics haven’t seen a problem with the wiring. You mentioned you replaced the wiring, and it fixed your issue. Did you replace the entire Engine Wiring Harness or just a certain part of it ?

Welcome to the forum… Sounds like you need to take your vehicle to an automotive electrical shop for repairs, or get a wiring harness and start by ohm checking the resistance at each end of each wire involved in the charging system… But 1st, do you have any fault codes using a scanner that can do an all module scan… Post codes (if any) here for better help… Also, did you install the correct AGM or Enhanced Flooded Battery (EFB)?? Not sure which one it takes… But installing the incorrect battery can affect the charging system…

Hey! Thanks for the welcome to the forum. I’ve had my car scanned for codes many times while I’ve dealt with this battery light issue (last scanned on Monday) and I still have Zero fault codes. The battery in my car is the OEM Battery which was replaced by the Infiniti dealership in late 2023 (under warranty). I also have a New OEM Alternator (replaced in Oct 2024 - under warranty).

You are welcome… How are you getting warranty work done at the dealer on a 9yo vehicle?? Aftermarket warranty?? And the dealer can’t find the problem?? Back to taking it to a specialty shop, like an automotive electrical shop that knows how to use a DVOM and check for resistance in all wiring involved… And you can confirm the dealer used OEM parts? I have seen many Napa’s, O’Reilly’s, ADV’s dropping parts off at dealers, I called a dealer once for a serp belt, (customer request) and they said call O’Reilly, that is where they would get it from to install… lol

New battery, New alternator, car runs fine but I still have a check battery light

Maintenance/Repairs

bing November 20, 2024, 4:22am 21

The dealer diagnosed and repaired it under warranty.

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New battery, New alternator, car runs fine but I still have a check battery light

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