I know- another flickering battery light thread. Well, my battery light flickers at idle and when I increase the RPM's, the battery light stays on steady.

Alternator or voltage regulator?

Since I started writing this thread, I decided I needed the voltage at the batteries while the truck was running and the battery light was on constantly no matter what RPM I was running it at. I checked battery voltage when the truck was not running and it read 12.6 volts for each battery. While running they read 12.4 volts.

What does everyone think?

 

alternator......with increased rpm its putting out more juice so the light quits.......time for a new one....

 

I say a reputable rebuild, alt..

 

I agree with the first 2 posts, the same thing happened to me.

 

I concur with all the above. But I would start by taking the alt. off and going to a parts store and have them bench test it. Also I would stay away from the remans done in Mexico or China.

 

As I've had a little time to think about why it quit on me, I remember when I was trying to start my new engine for the first time, I was not able to start it after many cranks. A short while later I realized my DP tuner was not pushed all the way into the CPM.

Since all that cranking drained the battery, I hooked up a charger and a buddy suggested I switch the starter over to START mode. I told him I thought that wouldn't be good for the electronics in the truck but he reassured me it wouldn't harm a thing. So I tried to start the truck with the charger on START mode at 75 amps.

Could that have fried my alternator?

 

The battery light was actually constantly on when I was at higher RPM's and dropped back down to a flicker at idle.

Now, the light is on no matter what RPM it's running at.

 

12.4V running = bad alternator. I agree that a good local shop is the best place for a rebuild.

I don't think cranking the engine with the charger connected damaged the alternator. Most battery chargers can't supply enough current to start a 7.3 on their own. When the engine is cranked, the voltage just drops too low to fire the injectors or turn the starter motor. The only electronics problems I have seen were from using a 24V battery charger/engine starter on a 12V vehicle.

Chris

 

HOW MANY MILES ON YOUR TRUCK?
It is possible that your brushes in your alternator are about to fail and near the springs. It could also have bad bearings and causing failure. Loosen the tension on your belt, slip the belt off and check your alternator shaft. You can not feel bad brushes but you most certainly can feel bad bearings. Check up down, left right, in out play. Have a good shop rebuild your alternator. They at least will put in new brushes and bearings. I would specify brand new bearings and ASK them how long to get the parts and get it done. Sometimes they have to order parts to get it done. I am sure they will not order parts unless they have your alternator in thier hands.
Dwayne

 

Also, what is your location?

 

Kansas City

 

218,000. The alternator is an aftermarket and I have no idea how long it's been on the truck.

 

If it is after market then just get another aftermarket and give them the core. No sense in rebuilding if it is not OEM. Check the parts websites for reviews on alternators before purchasing. I replied to the thread on soldering. I hope it all makes sense logically.
Dwayne

 

Thanks Dwayne.

 

I just replaced the alternator in my son's F350 yesterday while he was down visiting for the weekend from college.

I got him one of the O'Reilly re-manned specials with a lifetime warrantee and then gave him the volt meter I had plugged in my cigarette lighter and told him to glance at it every time he starts his engine from now on.

BTW, if I had been thinking, I'd have gotten him his own volt meter as preventive maintenance like Greg posted about way back when, in this thread: https://www.ford-trucks.com/forums/1...l#post10806422

I just ordered two more, one for my rig since I gave mine to my son and one for my Lightning since it only gets driven on weekends now.

Stewart