Okay so I've had a alternator go out in a vehicle before and I know the symptoms. I have an 05 f150 stx and the battery light is now coming on when I slow down, but my voltage is constant in the middle (where it's always been) and if I give it gas the light will turn off and reappear later. Or if it sits long enough the light will turn off aswell. Anyone have ideas? Just started today

 

Alternator appears to be on its last leg. Have it tested. Many places will do this for free.

The gauge in your dash is not like those long ago; they used to show actual charge in voltage readings. If you had a good tuner, they can provide instant charge readings. My Edge has this ability. My truck at idle shows a steady 14.1 volts charging; the dash gauge sits at the same point, and is pretty much useless.

 

Agree with Bucko 100%... and when you do replace it Motorcraft Only !~!~

 

When I had the same issue I had it tested at Oreilys and their machine said bad voltage regulator. When I opened up the alternator one of the bushings on the voltage regulator was worn down to nothing. I bought one off of Ebay for about $20 and it has been fine for more than a year now.

 

nice

 

My battery light and check charging system came on when leaving work yesterday. I had the truck in the shop and attempted to do the big 3 upgrade and I disconnected the alternator battery feed wire and reconnected it. Installed my ultra gauge and could see the voltage instead of the cluster gauge that's useless.. Was at 13.5 and then dropped to 11.8 and stayed there. Went to drive home and I beat on it at a light and the alternator kicked back on. I'm only charging at 13.5. It's been like that since I've bought the truck. Planning on getting a high output alternator when mine takes a dump.

 

well I thought it fixed. It didn't light came back on and battery is now dead. Guess I'll be buying a new alternator

 

Suggest a motorcraft.. you will thank me later .