I have a 98' and when attempting to head to work yesterday the Battery Light came and stayed on. I noticed several weeks back when the vehicle was in high RPM's (when getting onto the highway) the Battery Light would come on and go off when the RPM's would decrease. This weekend it changed from just high RPM's to the lights flickering when driving 70 mph. Now as indicated it is on to stay. Would this be the serpantine belt? Alternator? Will an auto parts store check this for me? How difficult is this to replace for a novice? What should I check first? Any help greatly appreciated.

 

I would probably get the battery load tested and alternator checked out. Your belt may be stretched out from age so I normally change that when the battery needs changed from age.

 

thats exactly what was happening to mime. the ALT was bad.

Disconnect the NEG. battery cable

remove the plastic cover on the throttle body

Use a 1/2" breaker bar to take the tension off the belt tensioner and remove the belt

Remove the two 10mm head bolts at the bottom of the ALT and one 8mm at the top on the little bracket.

Lift out the alt and unplug the harnesses and wire.

installation is just the reverse.

 

my 99 F150 just starting doing this, this past weekend.. Scared the crap out of me.. Was at 70mph it would flicker. Dash lights and head lights.. Glad I know what it is now and glad to see its a pretty easy fix.

Thanks