Alright, i can not figure this out.

1993 4.9 I6 2wd

OK! so when i have my air, headlights, and wipers going and i stop at a red light, my battery level goes real low and my headlights go dim. When i accelerate, my battery level goes back to normal and my headlights brighten. Also, if i was to drive through a puddle, my battery level also dips and there is a squeal. i have been beating my head against a wall, unable to figure it out

New alternator, battery is in good shape, belt doesn't appear to be worn and i am working on pulling codes, just got to find the damn scanner...

 

Could just be the gauge. Mine moves with my blinker, but not my stereo, which is way stronger of a pull. and I can watch it drop 2 letter in "NORMAL" on the gauge when putting windows up. Then I let off and it jumps back up.

The squeeling is water on the belt.

 

Check alt again, start truck pull pos off battery, if truck stalls bad alt, or if the lights dim while idling, might be battery. Even maint free batteries loose water.

 

sounds like the alternator

 

i would agreed til he said lights dim , im thinking belt tensioner is weak or belt is slick and slipping or both....engine off see if you can pull any slack in belt or engine running does tensioner bounce around alot also engine off remove belt and look at idler pulley see it ifs sloppy,, bearing could be bad on it , i havent looked to see if you have that. get a digital meter and check your alternator with truck running at idle then rev it up a lil and tell us what you get ........... wet belt nooooo i dont have any on my trucks that squeak squall or anything while 4wheeling and im headlite deep in some

 

im not a big fan of pulling battery cables off while running ,, reason being i had a overcharged battery blow up in my face from the spark lucky i had my safety glasses on but it ate my work uniforms up in couple hours cheap digital meter or a fluke 77 does the job for me

 

Ok, you can also check with a volt meter, if the alt is working, it should read about 13.5 or 13.8 volts, if not it will read 11-12 volts.

 

Sounds like the altenator isn't big enough output wise or has the wrong pulley on it. Sometimes they give you the wrong one.

 

mmmmmmmm hmmmmmmm only diffrence ive seen in pulleys are serpentine and v belt no size change in pulleys unless parts guy is high schooler or senoir and cant find right one says hey this 1962 model ford will fit looks the same.....back in the day maybe ..

 

i dont think i have a idler pulley but what i plan on doing is just replacing the tensioner assembly and throw a new belt on, and possibly get an alternator with a higher amp rating.

volts read perfect currently