i have noticed that my idiot light for charge is comming on when i rev over 3000. the lights also dim. it hsa been getting worse. it first started at 5000 than 4500. thanks

 

Hey Stonyman, You might need to replace the serp belt, but a bad alternator or belt tensioner can cause some headachs as well. Your belt might have lost the ability to grip at the higher engine rpm. The alternator might have worn parts as well. Look under the Electrical wireing section. I am sure someone has a tip for you.

Dave Powell:-X12

 

You can't tighten the belt like you used to be able on the older trucks with non-serpentine belts. The serpentine belt on your truck is tightened by the belt tensioner, an idler pulley that has a spring in it. That can be worn out. You need to check the tensioner, the belt and if that doesn't help, your alternator.

HTH, George

 

If you've got a multi meter that can read DC Volts, you should be getting around 14 volts when the truck is idleing and no accessories turned on. It should be about 12.5 volts shut down too.

Start turning on your accessories and see which one drops it below 12v. Could still be a 'bad' alternator, even if it's pumping 14v at idle and no load. Maybe not able to handle the amps required to maintain +12v. Could also be the battery?