2002 Silverado battery light on

[Rat407]

I'm thinking this is an alternator issue but wanted to get other ideas.

My 2002 Silverado has 160k miles on it. This is the original alternator. When I first start it after it sits for a few hours, basically when it is a cold start. The battery light comes on and stays on until I bring the rpms up. What is also weird is I have a Scangauge II installed and the display will not come on until I bring up the rpms.

When I first start it, the volt gauge on the dash is showing 10vdc. When I bring the rpms up it goes up to 14.2 and the ScangaugeII comes on and it shows 14.2 as well and the battery light goes out. From there on out it runs fine. No other issues with the light coming on. Driving it around the ScanguageII shows 13 to 14vdc.

All my electrical connections are clean and tight, as well as all the grounds.

Do you think this is an issue with the regulator inside the alternator?

I was going to pull it off and have it rebuilt. Not a fan of getting one off the shelf at AZ,AA, CQ or O'Rileys.

 

[901Memphis]

Yep classic Gm alternator symptoms. Getting it rebuilt is a good idea if you have a rebuilder locally. If you buy the tough one new unit from advance it will come from Remy power like I did with mine and you can use coupon codes.

 

[Rat407]

Thanks, that is what I was thinking. It also gets hot to the touch after a simple 4 mile drive. Too hot that you can't hold your hand on it.

 

[901Memphis]

This one is showing as Delphi on the picture at AA, if you have that option available and the re builder doesn't work out.

http://shop.advanceautoparts.com/p/carquest-alternator-new-105-amps-8247an/15580004-P

Use code TRT41 to save $40

 

[Rat407]

Just called the place here and they can rebuild it for $86. He said it sounds like the slip ring is worn with that many miles on it. Can get it rebuilt in a few hours if the work load isn't high when I get it into them. Sounds like a plant to me.

 

[901Memphis]

Yep they will do much better work than the ones that got rebuild in Mexico from the parts store

 

[daman]

Having them put new bearings in wile there in there is always a good idea too. But they usually do.

 

[HerrStig]

Originally Posted By: Rat407
Just called the place here and they can rebuild it for $86. He said it sounds like the slip ring is worn with that many miles on it. Can get it rebuilt in a few hours if the work load isn't high when I get it into them. Sounds like a plant to me.
The carbon brushes usually wear out before the metal rings. A brush set with regulator components is less than 20 bucks. If you can get to the back of the alternator it's an easy job.

 

[pcoxe]

Could be one shorted rectifier. I think they have six. Basically, five are providing power and one is draining power.

 

[George7941]

Re the ScanGauge, you can turn it on before you start the engine by just pressing the menu button. This way, you can monitor battery voltage on the ScanGauge while the engine is idling before you rev up the engine.

 

[Rat407]

Originally Posted By: George7941
Re the ScanGauge, you can turn it on before you start the engine by just pressing the menu button. This way, you can monitor battery voltage on the ScanGauge while the engine is idling before you rev up the engine.


I didn't know that. Thanks.

 

[Rat407]

Took the alternator off and had it rebuilt. The place tested it and it showed good. But when I picked it up he said it was amazing that it was putting out any power at all. The brushes were gone and the slip ring was shot. So it is all back to new with new bearings and all and out the door for $75.

Not to bad since a new Delco at Advance Auto was showing $174.

 

[George7941]

What engine do you have in the Silverado? My Sierra has the DR44G 140 amp alternator, I wonder if you have the same one?

Your brushes wore out over 160K miles. I plan on replacing the brushes and bearings in my alternator once it reaches 120K miles. It currently has 95K miles. I would like to replace the brushes before they wear out and destroy the slip rings.

 

[Rat407]

It is the 105 amp alt on the 5.3 engine.

 

[901Memphis]

I would like to check the AAP new unit and see if it's actually a Delphi which would be more appealing than a rebuilt since you can use the $40 off 100 code to make it more affordable

 

[The_Eric]

Doubtful. Just because the case has "Delphi" cast into it, does't make it a new Delphi unit. Those are usually just old cases with new guts- that's how they can call them new.

 

[901Memphis]

Yeah that sounds right. Like i said i bought a toughone new alternator from AAP before they started calling them carquest and had it shipped online to my door and it was in a remy box and labeled remy which i consider a good part. Been on there over a year now and it always puts out good voltage. Lifetime warranty if it ever does die.