Battery light on after replacing alternator

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

jfwhit

TYF Newbie
Joined
Jul 22, 2014
Posts
19
Reaction score
3
I have a 2003 tahoe Z71. I replaced the alternator 3 months ago. The battery light came on just now with the gauge still reading 14. So I assumed the alternator was bad. So I replaced it. The voltmeter shows the battery at 14.26 while running. The alternator is new. Not rebuilt. The battery light is on while driving. And stays on for a couple of minutes after I turn the tahoe off. I’m at a loss as to what the issue could be. Everything is working fine. Wondering if it could be a instrument cluster issue. The battery is 2 years old. It strarts great. I unplugged the negative cable for a few minutes. Nothing works so far.

Any idea Since?

Thanks
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,619
Reaction score
26,349
Location
Treasure Coast, Florida
I have a 2003 tahoe Z71. I replaced the alternator 3 months ago. The battery light came on just now with the gauge still reading 14. So I assumed the alternator was bad. So I replaced it. The voltmeter shows the battery at 14.26 while running. The alternator is new. Not rebuilt. The battery light is on while driving. And stays on for a couple of minutes after I turn the tahoe off. I’m at a loss as to what the issue could be. Everything is working fine. Wondering if it could be a instrument cluster issue. The battery is 2 years old. It strarts great. I unplugged the negative cable for a few minutes. Nothing works so far.

Any idea Since?

Thanks

What is the battery's voltage with the engine off? What kind/brand of alternator did you use?
 

adriver

Full Access Member
Joined
Aug 18, 2018
Posts
782
Reaction score
466
Check all your connections. Are you saying you turn it off, key out, battery light stays on then?

What size was your old alt and new alt? (There's 2 sizes, just making sure).
 
OP
OP
J

jfwhit

TYF Newbie
Joined
Jul 22, 2014
Posts
19
Reaction score
3
Check all your connections. Are you saying you turn it off, key out, battery light stays on then?

What size was your old alt and new alt? (There's 2 sizes, just making sure).

Yes. Engine off. Key out. Light stays on a little longer than the interior lights. 145 amp. I want to say the old was 105. It was 3 months ago. My best friend owns his own shop. He ordered this from O’Riellys. He said at that time to get a bigger Amp alternator with the wider belt. So I’m assuming that it had the 105. I didn’t pay attention when I removed it. Also it’s been 3 months. But it’s been fine until a day ago. I went back to his shop yesterday. He warranted. Put the new one on and the light stayed on. We are just brainstorming to figure this out. So I thought I’d ask here if anyone has had this same issue. He’s never seen it. He’s had this shop 30 years and he’s a Chevy guy himself.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
26,260
Reaction score
39,384
Location
Stockton, Ca.
I would clean and check your ground wires even if they look ok, remove them and sandpaper a little to get a fresh contact and see if that makes it go away, if not then if you have a shop around that does instrument clusters they may have a test cluster that you can just plug in and see if it is the cluster or a good junkyard probably has a used one it wont hurt anything to just plug one in and try it, if that is the problem then you would just need to have the mileage programmed to match your old one. If that is still not the issue then I would move to the ignition switch.
ultimately the best option is to hook it up to a tech2 and run some test's/scan for body codes.
 
Top