big-o

Hey fellas, I was just driving in my 97 4.6L 4wd f150. Yeah, she is getting old but she looks great. While driving, I was going up a small hill and as the engine started laboring a bit and the rpm increased over 2000 rpm to maintain speed, the battery light on the dash started flickering and as soon as I take my foot off the gas or slow down, the light stops flickering. If I hold the truck to continue accelerating, the light will go solid and remain so until I slow back down. I assume I am looking to the alternator. What says you? I really appreciate your help. Thanks....-Greg o

Aragorn

If you haven't check and clean the battery contacts but I'd look towards the alternator, battery, or belt slippage. What kind of voltage are you getting from the alternator with the engine running?

How old is the battery and what kind of voltage do you see when the engine isn't running?

akdoggie

Alternator

white89gt

X3 - Alternator tater....

Jbrew

Check the in line fuse first in the alt harness. They can vibrate loose and short in the holder, cause an intermittent bat light.

Also if the light stays on, open the holder and put pressure on the fuse. The holder itself can go bad.

white89gt

Good call Brew!

Jbrew

Thanks, yea when that's the case and when you put pressure on the fuse you can hear the alt kick in and draw a little more power from the engine..begins doing it's job again. Sometimes you'll even get a whistle or a slight whine lol.

OhioLariat

Although it could be the fuse - and that bears investigation - I'm betting alternator, as well. The (repeatable) RPM-related symptoms you describe are exactly what mine did when the brushes (and slip ring in my case) became toast. Mine started doing the light show around 3800 RPM, then got got progressively lower.

If you're mechanically inclined, I'd suggest rebuilding it yourself (it's not that difficult, especially if it just needs brushes) or having a local shop do it vs. getting a parts-store reman. I actually rebuilt two, and have a spare on the shelf. I think white89gt has about 23 of them lying around.

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big-o

Thanks guys! The weather is finally better today and I'lll be able to get out and take a look. Outstanding comments and ideas. Thanks again!

Raybz

Dont you mean they will lose contact or OPEN in the holder?
A fuse after all is a short when it's good