Alternator question

[mr tahoe]

hey guys im having a problem with the power in my truck lights flicker when not accelerating rpm goes down a little bit and the engine shakes, i hear a whining noise from speakers too not sure its the alternator since the truck starts like it should, not sure what to look for

 

[drakon543]

Well it is possible for an alternator to go bad in a way where it's only capable of maintaining the battery and most of the vehicles functions. It's also possible to only loose one cell in the battery dropping the voltage down but still capable of starting the vehicle. There are a few other things to note about those systems that could cause issues but you can easily test most of those. With the truck shut off the battery should read 12+volts with a basic meter if it doesn't you need a battery. With the truck running it should read 14+ if it doesn't you need an alternator. The other test can be done during the night easier. But anyway start the truck and have it pointing at the garage or a wall whatever allows you to see the headlights the best. With that start turning everything on, hi beams a/c everything electric. If the truck dies or the headlights get real dim without coming back your voltage regulator is bad which is probably part of the alternator. The old trick of unhooking your battery probably won't tell you anything and isn't recommended as most newer vehicles need a battery in the loop to function.

 

[mr tahoe]

Guys i got really lucky i cleaned the battery terminal and all is good

 

[ccapehartusarmyINF.(ret)]

the dirty battery terminal was causign high resitance in tern wich causes a voltage drop