Went out to make a run to dump and battery is dead. Drop in my back up, make my run, park the truck. Battery dead the next morning. Other battery is now fully charged and dropped back in truck. Came home from a trip 10 days later and truck had not been moved, flip the key and dead again. How can I go about diagnosing the problem properly without replacing a bunch of parts unnecessarily? I am getting a whining sound around the alternator and it's hot to the touch after running only a few minutes. Not the same sound as powersteering pump. 89 F150 XLT 5.0. I really need help from the experts, can you help? Nearest parts place sells Remy alternators supposedly new. What do you think? Thank you!

 

Check and make sure no lites are on, such as the glove box or underhood might be stuck on. There might also be a short that is why the alt might be running hot

 

or the alt. is going bad... a squeeling alt is usauly a dieing one.... go up to your local auto parts store and have them test it

 

Its easy to do a home test, loosen the pos, start truck, pull pos off, if truck keeps running alt good, if truck dies its the alt. Also, 99% of time it is bad brushes, BWD or Standard ign makes a brush set for about 10.00. I replaced them on all my Fords when the alt stops working. They work still to this day.

 

Thank you for the advice! Good place to start. I'll give it a shot tomorrow and let you know how it pans out.

 

The whine might also be the belt or tensioner pulley.

 

Do you know the part number for the brushes? Can you get them at your local autoparts store?

 

Tried this test. It didn't die but it started idling very erratically. Smoothed right out when I put the connector back on the battery. I only ran it for a minute or two and the whining in the alternator is still there and the housing got bloody hot quickly. Would you concur the alternator is toast?

 

maybe not toast but on its way out... pull it off and have a parts store test it just to double check... if you have to replace it, it already off... if it tests good (i dont think it will) you can count that out and test other things from there