alternator is not charging battery. i had it tested and it tests good.


Asked by Jul 28, 2014 at 04:52 PM about the 2003 Chevrolet S-10

Question type: Maintenance & Repair

I have a 2003 S10 with a Vortec V6. I was driving on the hiway when the battery light
came on and the truck quit. I put a new battery in and noticed that the volt meter was
showing that the battery was not charging. I removed the alternator and took it to be
tested. It tested good. I put it back in the truck and it started to charge again. After driving
for a few days I noticed that it had stopped charging again. The cables seem to be in good
condition. Any ideas?

12 Answers


It looks like your trucks charging system is computer controlled, have the engine control system checked, the fault might be in the ECM.

1 out of 1 people think this is helpful.

Can I check this on my own or does it take a professionals diagnostic system?


It will take some specialized equipment to make the ECM cycle the Alternator during the test, so a Auto tech would be a good idea.

Best Answer

Thanks for help.

John Carson

Great advice "tennisshoes". Also have the battery tested. I don't know how old your battery is, but if it is original in a 03 vehicle, it may be bad. One cell will not allow it to hold a charge or even charge. You also may have a diode going out. Electrical that gives problems intermittently is a B to locate and fix unless it is tested by good diagnostic equipment not normally found in a home garage.

1 out of 1 people think this is helpful.

my s 10 is charging went it start but as i am driving it it stop charging as i step on the gas i let go of gas and it start to charge and it dose it all the time now

1 out of 1 people think this is helpful.

So either the belt is slipping under load or the alternators internal regulator is starting to fail and I have seen a flying open do the same thing, works at low RPM but the circuit open when RPMs increase it shuts down.

1 out of 1 people think this is helpful.

I took it to a Chevy dealer and had it diagnosed. The alternator was bad.

Ika Irakli

Mine is doing the same thing. almost 100 percent sure it's an alternator. Pain to remove it from the side of a wheel well

Henry Knipschild

Ugh big time charging problems with 2001 Chevy S10 2.2 liter. Alternator tested bad. Installed a new alternator worked for 2 days quit charging. Checked all cables and connections. New alternator was bench tested and was good Reinstalled and same problem not charging .Checked fuses and can not find anything. Any suggestions? .


Is the ECM turning on the alternator?

Henry Knipschild

Not sure I had 5 volts on the small red wire. I gave up and took it to a shop to trouble shoot. I let you know what they find out.

Your Answer

Add photo

Related Questions


Looking for a Used S-10 in your area?

CarGurus has 1,822 nationwide S-10 listings starting at $1,749.


Search Chevrolet S-10 Questions

Chevrolet S-10 Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 1,970
#2 John Saffrahn
John Saffrahn
Reputation 880
#3 Trebor66
Reputation 840
View All

Related Models For Sale

Used Ford Ranger"
252 Great Deals out of 7,808 listings starting at $988
Used Chevrolet Silverado 1500"
2,381 Great Deals out of 143,344 listings starting at $1,195
Used Chevrolet Colorado"
333 Great Deals out of 17,731 listings starting at $2,495
Used GMC Sonoma"
5 Great Deals out of 577 listings starting at $1,995
Used Toyota Tacoma"
632 Great Deals out of 30,001 listings starting at $2,850
Used Ford F-150"
3,170 Great Deals out of 215,803 listings starting at $1,000
Used Dodge Dakota"
151 Great Deals out of 4,812 listings starting at $900
Used Chevrolet Blazer"
1,628 listings starting at $1,891
Used Nissan Frontier"
465 Great Deals out of 20,641 listings starting at $2,500
Used GMC Sierra 1500"
1,032 Great Deals out of 55,960 listings starting at $2,400
Used Dodge Ram 1500"
539 Great Deals out of 13,899 listings starting at $995
Used GMC Canyon"
115 Great Deals out of 8,368 listings starting at $1,500
Used Ford Mustang"
724 Great Deals out of 41,223 listings starting at $900
Used Chevrolet Camaro"
813 Great Deals out of 39,041 listings starting at $2,650

Used Cars For Sale

2004 Chevrolet S-10 For Sale
68 listings starting at $2,695
2003 Chevrolet S-10 For Sale
4 Great Deals out of 425 listings starting at $1,749
2002 Chevrolet S-10 For Sale
278 listings starting at $2,450
2000 Chevrolet S-10 For Sale
282 listings starting at $2,500