6.6 alternator issue

[Bigtwin88]

I have 2009 Sierra 2500 HD with the Duramax. I also live in Ontario Canada not sure if that makes any difference. Anyway I recently noticed my volt meter when first starting the truck it does not come up to full charge it does come up to the first line I don't know what The voltage would be there. But after about 3to 5 min. It would come back to proper voltage which around 14 volts. I was told by someone that the Duramax has an air box heater I am guessing this intake air. I was told that this heater uses a lot of power and that's why the voltage does come to full voltage right away. Is this in fact true or is my alternator in fact pooched. Any help would greatly appreciated. And I'm in the wrong forum sorry and I'll move it

 

 

[markw8]

I don't know about the heater but what you see with the guage sounds normal. Alternater output is computer controlled.

 

Mark

[Bigtwin88]

Thanks but I happened to come across another forum that does mention the air box heater as the culprit

[Shaners]

I know it isn't comparing apples to apples, but my '05 Dmax guage goes to 14+ volts as soon as it is running.

[markw8]

My 08 is similar to the OPs.

 

Mark

[mkayler]

Mine does the same thing. Takes a little while and goes up to 14 volts. I never noticed till you mentioned this.