Battery Light Issues and Hard Starting HELP

nsaylor · November 2, 2013

I'm hitting the end of my rope with a problem on my 2005 Silverado 1500 (4.8 120k).

I have had no issues with my truck for a long time, but a few months ago I had a hard start, and the battery light stayed on after I started up. I managed to get to work and it restarted afterward regularly with no light. After that (a period of a couple of days) it would start hard about 2/3 of the time and the light would stay on, but occasionally would start normally without the light.

I took it into sears at that point to get the charging/starting system and battery checked, at which point they told me the battery was fine, and that I needed a new alternator. I got a reman (BBB brand) alternator from my local jobber supply house, popped it in started it up, no light, felt good.... then one start later it started happening again.

I got frustrated and just drove it as it was for a couple of days, when out of nowhere the problem went away completely. All was well.....

Then it came back worse a week ago....BAD

REALLY hard starting (as in slow labored cranking, but always manages to start), and even died at an intersection once, which it has never done before. 8 out of 10 starts the light comes on and stays on, and even when it starts "normally" it sounds like it's working harder to start than it used to. On taking it back to Sears they say everything checks out fine. ARGH!

Thoughts:

I always understood that the alternator on this truck is controlled by the PCM to save fuel. Is that correct? and if so could that be the issue?

I know people like to point to the replacement alternator as the culprit, but it tested out good.

Any help is appreciated.

txab · November 2, 2013

Check all cables and grounds, connections. Cables can go bad internally, been many on here report that. Have the system re-checked. Battery load tested. Starter checked. Alternator checked. Have you checked for any stored codes?

scottmoyer · December 12, 2013

I know this is old, but you never posted your fix. It was the battery, right? I had the same issue and my battery was only 3 years old and was a 60 month battery. Got a new one and haven't had a problem since.