charging problem

[travlinman and wife]

2000 f150 alt light flashes at low rpm  but goes out at higher rpm. I supect   alt but have not had chance to check temp 23 deg in tn this morning.

 

[John61CT]

Ideally measure Volts and Amps output

with either battery run down a bit, or with heavy loads, headlights, fans, crank up the stereo, etc

at idle, high idle, and 3000rpm.

May well be OK for a while.

Carry a quality "pocket" jumpstarter sized for trucks.

 

[AJ452]

Many auto parts stores will test the alternator for you for free.

 

[tx2sturgis]

Could just be the belt, or tensioner/idler pulley.

Or it might be the alternator itself.

Does it do it every time? Or did it just start doing this recently?

Is the alternator making noise?

Are you having problems starting the vehicle? 

More information and/or testing is needed.

 

[Vonbrown]

Check your drive belts.

 

[B and C]

I'm with Vonbrown. An old glazed and cracked alternator belt would surly slip when cold.

 

[highdesertranger]

I have a 01 F-250 it has several electrical issues. the battery symbol flashing on and off is one of the issues and there is nothing wrong with the alternator. check your alternator but it might be nothing except Ford's funky electrical gremlins if you do a search you will see that they have plenty of them. highdesertranger

 

[travlinman and wife]

thanks for all the help . I did get a chance to check it today and the alt is bad.

 

[frater secessus]

Thanks for the followup with diagnosis.

 

[highdesertranger]

yes thanks for the follow up. highdesertranger

 

[Vonbrown]

Excellent