Battery light flickers when cold then goes away when warm

[hardware_failure]

I just replaced a bad alternator in my 1990 sierra. Got a POS from autozone.  (I've heard that auto zone alternators are crappy, but I had to get to work yesterday and didnt have a choice)

 

Everything seemed okay 2 nights ago when I changed it.  Last 2 mornings now tho when I start the engine the battery light flickers for about 3 min while cold then turns off right at about 3 min when the truck gets warm.  I do notice the voltage is rather low then shoots right up when the light goes off. (alternator starts working basically)

 

Is this the belt slipping?  Could it be bad wires or the alternator pulley?  I checked the battery leads and wires and they look fine..

 

Thanks.

[Duelin]

If you just changed it the belt shouldn't be loose unless you didn't get it tight. When it is cold before you start it check battery voltage should be around 12.5 volts. And after you start it check the voltage while the light is flickering. It should be above 13.5. Usually they are around 14.5 volts. If it is below 13.5 exchange the alternator.

[hardware_failure]

I didnt replace the belt. I brought it in and while it has a few tiny cracks, the guy at autozone said that my gatorback belt was better that then stuff they stock now and that I have a few more years in it.

 

Its very tight, in fact it was kind of a pain to get it back on even with the tensioner pushed all the way back.

 

I have a multimeter here at work.. just went and started the truck and its fine now. I expect it will be acting up again tomorrow morning when its sat for 12 hrs in the cold tho.

 

If I check it while its acting up I expect it will be under 13.5 until the light goes off. Like I mentioned both mornings I watched the dash instantly shoot up to 14 the second the light went away. I guess Ill see tomorrow.

 

If I replace the alternator again and it still does this what else might it be?

 

Thanks for the response.

[waumo1]

Have them test the alternator and give you a new one. I have had bad alternators straight out of the box, both re-manufactured and new ones.

[Dirtautoguy]

Maybe try checking for good connection at the battery and wire connections.