Battery having trouble holding charge

ANSWER : Hello. If the battery and the alternator are new and if it is verified that the alternator is charging then you have an issue with programming. When you replace the battery on this vehicle the computer needs to be reprogrammed to recognize it and to properly charge it. If this is not done then the computer will not turn on the alternator at the correct times an this battery light will come on. You need to have this programming done by a certified mechanic, like one from YourMechanic, who can come to you to [program the battery into the computer] https://www.yourmechanic.com/services/battery-light-is-on-inspection

ANSWER : Hi there – this behavior sounds more like there is a parasitic load, or drain, on the battery after shutting it off. This problem can be diagnosed by connecting an ammeter to the positive (red) battery cable, observe the current drain (likely less than 1 amp), then, one at a time, remove each fuse, check to see if the current drain has dropped to near 0, then reinsert the fuse. This process should identify the faulty circuit in most cases. The specific components on that circuit can then be checked for current drain problems. A professional mechanic, like YourMechanic, can come to your location, and perform this procedure for you, and replace/repair the failing component.

ANSWER : Hi, thanks for writing in. A battery is supposed to last for three to four years in most cases. Some of the causes of premature battery wear may include a broken alternator, damaged battery terminals, or battery temperature sensors. Before heading to an auto parts store, you should contact one of our local mechanics to inspect the source of your battery draining issue. This way, the precise problem can be determined; hopefully finding the root source and fixing the problem affordably. We can also perform replacements for you if that is needed.

ANSWER : Hello. Most of the time the issue is in the wire coming from the battery to the alternator. This small wire has a tendency to fail and have high resistance. This needs to be checked first. If that is not the cause then you may have a computer issue. I would need to check that with a scan tool that will communicate with the vehicles main computer. If you are looking to have this done, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the vehicle is not charging] https://www.yourmechanic.com/services/battery-will-not-hold-a-charge-inspection

ANSWER : Hello. If the battery continues to drain overnight despite recent replacement, then there might be some sort of electrical short or malfunction somewhere on the vehicle that is draining the battery. A good battery should hold a charge overnight without any issue. A simple load test should be able to determine if the battery is good or not.

There is also the possibility that you may have the incorrect battery. Your vehicle uses a 4.6L V8, and has a considerable amount of electronic accessories, and will experience all sorts of issues if the incorrect battery is used. I would verify that the battery is the correct size, and able to hold a charge, and then move on to examining the possibility of an electrical short. If you need further assistance with this, a certified technician from YourMechanic can inspect the battery firsthand to pinpoint the problem and make appropriate repairs.

ANSWER : Hi There,
What you are describing is most likely a faulty alternator. The alternator charges the battery while the engine runs by generating amperage and recharging the battery while the engine turns the alternator pulley. The voltage regulator is a unit that regulates the charging of the battery by the alternator and maintaining a certain amperage while the engine runs. When the alternator is not working properly, this may result in the battery quickly losing charge and the car losing all power. You may also notice a whining sound as a result of the bearings inside the alternator begin to fail. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your charging system.

ANSWER : Hello, thank you for writing in. Several things may be going on. The installation of the new alternator needs to be verified, focusing on the electrical connections and the drive belt. Make sure the connections are clean, dry, and tight. Make sure the drive belt is routed properly and is tight on the alternator pulley (as it is what powers the alternator). If the installation was fine, you will want to make sure the alternator was not faulty from the factory. It is not common, but these issues have been known to happen. Most automotive parts stores can test the alternator off of the vehicle. If you would like more help with testing, contact our service department to schedule an appointment.

ANSWER : With all the playing around, the battery going dead more than once, and it being over 5 years old, I would try replacing the battery first.

After the battery is replaced, lock all the doors and then unlock the vehicle with a remote or door keypad if you have one equipped. Next, using an original key, see if it will start. If it doesn’t then the vehicle may have locked you out. In this case, only a WDS scan tester at a dealer can regain access to the passive anti-theft system for you. Unfortunately this would mean that you’ll need to tow it to a dealer.

If you decide to get this fixed or would like a second opinion on this, get the car looked at by a qualified technician, such as one from YourMechanic. A mechanic can perform these checks to properly diagnose your dead battery and fix it accordingly.