Charging system problems

Asked by Apr 14, 2017 at 10:05 AM about the 2005 Ford F-150 XL

Question type: Maintenance & Repair

My battery keeps going down after about  after the engine is shut off for about
36 hours. I have replaced battery, positive and negative battery cables, and
alternator. The problem still exist.

2 Answers


Either you have a bad battery or there is a parasitic draw on the battery. To measure the draw remove the positive battery cable and connect an amp meter between the positive battery post and the positive battery cable. This will measure the draw. Make sure any under hood lights or interior lights are turned off. To locate the circuit drawing the current you can remove and reinstall one fuse at a time until the draw stops. Then you have found the problem circuit. Once you have found the problem circuit then you examine all of the things in the circuit until you discover the problem. Common sources of parasitic draws are defective alternator, hood light stuck on, glove box light stuck on, interior lights on, stuck relays, etc.

2 of 2 people found this helpful.

timers and such can raw some juice for up to half an hour so give it that amount of time for problem to show . From memory 50 milli amps or more is too much , or search parasitic draw , let us know what happens .

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