05 Silverado Weak Starting

[camo kid]

I have a 05 silverado Z71 crew cab and have had problems with weak starting.When I turn the key on the clock always starts at 12:00 and the head lights are dim.The truck starts very weak and on occations just clicks.The voltage gauge normally reads around 14 when the engine is running,but sometimes dropps to around 13.The battery was replaced and 3 or 4 months ago and when I check the battery and altenator they check out fine.What could be causing this issue?

[gmtech4]

who and how did they check it ??

 

you need a battery load test

 

starter draw test and

 

alternator output test ,

 

all done with an AVR machine

 

 

3-4 months means nothing

 

good luck

[Westlotorn]

Put a voltmeter on the battery, have someone turn the key to start the vehicle. If your volts are reading 12.7 or so before you attempt the start you should see a drop of no more than 1.5V when cranking.

 

If it drops more than that you have a battery issue.

 

IF your voltage before starting is lower than 12 you have a charging issue. Test your alternator.