Starter or Alternator?

[CharScott85]

I have a 2005 Ford Explorer Eddie Bauer 4.6L. 2 weeks ago I bought a brand new battery, because it wouldn't start one day. Considering the battery was about 4 years old...I thought I would need a new one. I got the battery, my truck drove fine up until last Thursday. Went to crank it up, and it wouldn't start. I got a jump, drove to work with no problems. Got off work the next morning...again it wouldn't start. So I got a jump again...drove fine all the way home. So I did the usual simple test. Wipers work fine, Radio work, lights doesn't dim, lights on dashboard all work. The truck just doesn't want to start after shutting it off, but does drive fine once jumped. The dashboard messages is saying my "Charging system" is ok, Battery volts is low (when driving it fluctuates between 12.4-13.0), when idle it's at about a 13.0v. I'm also getting the 9318, 9354. and D900 codes. I have no check engine lights or battery lights (usually when alternator is bad). This is throwing me off a bit. I don't want to take it to a shop and get parts I don't need, or take it for something I could fix on my own...Any suggestions?

 

[Tech By Trade]

Have a real close look at the battery cables. The + likes to corrode back behind the plastic, especial if the old battery was gassing. Give it a base dip in a pail of baking soda and water.

 

[CharScott85]

Have a real close look at the battery cables. The + likes to corrode back behind the plastic, especial if the old battery was gassing. Give it a base dip in a pail of baking soda and water.

The + terminal did have a little corrosion around it before I got the new battery, and it does have a little around it. I'm going to try this in a few hours and let you know what happens

 

[toypaseo]

Check the battery cable inside the battery terminal. I had problems with turn key, click, and everything dead. Corrosion inside the battery terminal was the issue. No problems since I switched to aftermarket 100% brass terminals and treated battery terminal felt washers.

 

[BrooklynBay]

Check the ground cable terminal for corrosion. There might be corrosion between the frame, and the end of the terminal (not just where it connects to the battery). Use antioxidant on each terminal.

 

[CharScott85]

Sorry for the late update. Battery died in truck, so I had to get a locksmith to unlock it. I tried everything suggested. Truck still wouldn't start without a jump. Drove to work fine, but turning signals wouldn't work and still have to get a jump. Alternator? If I check the alternator, what voltage should it be putting out?

 

[BrooklynBay]

Charging systems vary depending upon the model since they use a different alternator. An average voltage is 13.5 to 14.5 volts.

 

[kmack]

Check your voltage at the battery with the engine running. Anything less than 13.5 volts at the battery terminals and I'd look at your alternator.
Also, check your standing voltage at the battery (engine off). Check this after a couple hours of sitting (not running). You should see at least 12.5 volts on the battery. You can also leave the volt meter on the battery for a minute or two to verify you don't have a voltage drop. If the alternator checks out ok, and the battery checks out ok, it's possible you have a drain on the system.

This gives an idea on how to check for a parasitic drain on the system: How to Find and Stop Car Battery Drains – DIY Car Battery Tests