02 yukon charging system issue

[Gonzo]

Need some help guys. 02 yukon. Batt light came on, changed battery and alternator tested bad.. changed it too. Now I have an intermittent batt light flashing. I went to the parts store to retest the alternative and it tested good. They thought maybe a loose tensioning pulley. Changed that but no effect. Light is still flashing. I have triple checked all the connections and cleaned the grounds, all didn't help at all.

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[jk13]

Engine to chassis ground strap?

[Fullpass]

I had changed an alternator on my 03 Chevy Silverado. The alternator came with a bulletin in the box that said the code in the vehicle may half to be reset...Sure enough I had a code something like charging system..Autozone wouldn't reset it, but Oriley's did, they reset the code for me..my rpm was fluctuating couple hundred rpm up/down. Reset code on vehicle...held steady.

[Gonzo]

Engine to chassis ground strap?

Gave that a go already and it didn't help,

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[Gonzo]

I had changed an alternator on my 03 Chevy Silverado. The alternator came with a bulletin in the box that said the code in the vehicle may half to be reset...Sure enough I had a code something like charging system..Autozone wouldn't reset it, but Oriley's did, they reset the code for me..my rpm was fluctuating couple hundred rpm up/down. Reset code on vehicle...held steady.

I go have a code reader I will give it a try, thx

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[Gonzo]

The Code reader didn't pick anything up, the internet tells me that the battery light itself doesn't code on these models until the engine starts to lag.... and then it will be other codes about missing and such.

[Wakerider16]

All your connections good on the alternator? If you haven't already maybe put some di-electric grease on them to see if that helps.

[Gonzo]

All your connections good on the alternator? If you haven't already maybe put some di-electric grease on them to see if that helps.

I will swing by and get some today, was thinking about changing the connector as well. And the belt

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[Gonzo]

Goo did not work

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[clrussell]

I'll come back to this later for some help. I just saw it


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[Shaun R]

How many volts is it pulling while the motor is running? Check the amp draw as well. Test it with the least amount of draw, no AC and lights off. Could have something gong bad that's pulling enough amps to trip the light.

[clrussell]

I forgot about this when I was back at the shop earlier. I'll look up a couple test charts for you in the morning to pin point where you need to go.

I've also seen the battery connection at the jump start post cause problems so check it to make sure it's tight and clean.

What brand alternator did you install? New or reman?


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[BudmanV24]

Make sure all the positive and ground cables still have solid terminations. I feel like 02 might fall under the years of failing cables where the connection between the cable and cable end corrode and fail to transfer power.

[Gonzo]

I forgot about this when I was back at the shop earlier. I'll look up a couple test charts for you in the morning to pin point where you need to go.

I've also seen the battery connection at the jump start post cause problems so check it to make sure it's tight and clean.

What brand alternator did you install? New or reman?

Reman/Delphi/130amp


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How many volts is it pulling while the motor is running? Check the amp draw as well. Test it with the least amount of draw, no AC and lights off. Could have something gong bad that's pulling enough amps to trip the light.

Not sure, I need to find my volt meter and re-educate myself on using it. The guys at the parts store say everything tests correctly.

Make sure all the positive and ground cables still have solid terminations. I feel like 02 might fall under the years of failing cables where the connection between the cable and cable end corrode and fail to transfer power.

checked and double checked all the endpoints, if something is cut or bad in the middle I havent found it. The only thing I havent done that may need it is to change the plug but it looks good to me and the parts guy agrees nothing is loose.

I did find out last night that there is a different serpentine belt for the 130amp alternator than the original 100amp. The guy who sold me the 130 forgot to mention that, so I think I am going to change the belt next. Its only 30.00, but I am starting to feel like I should have taken it to a garage the way I am nickle and dime-n myself with different things...

[clrussell]

Not sure, I need to find my volt meter and re-educate myself on using it. The guys at the parts store say everything tests correctly.





checked and double checked all the endpoints, if something is cut or bad in the middle I havent found it. The only thing I havent done that may need it is to change the plug but it looks good to me and the parts guy agrees nothing is loose.



I did find out last night that there is a different serpentine belt for the 130amp alternator than the original 100amp. The guy who sold me the 130 forgot to mention that, so I think I am going to change the belt next. Its only 30.00, but I am starting to feel like I should have taken it to a garage the way I am nickle and dime-n myself with different things...

So yours has the factory 100 amp and you put the 130 amp on there?

Belt Wong cause the problem unless it's not turning the alternator, you would hear it squealing if it was slipping bad enough not to charge the alt.

If yours originally had a 100 amp and you put the 130 on it try taking back the 130 and putting the 100 on it and see if it fixes your problem. Some rigs won't accept the alternator because of the way the plug is wired differently on the two.


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