Hello everyone, I have a 2005 Ford Focus With 140k miles on it. I have replaced a lot of parts including the alternator and the battery and both have been tested after the point and tested fine. Well, when I park my car after work and it sits over night until morning it barely has any power. Enough to power the auxiliaries but not to start. My negative terminal is very corroded and loose and wasn’t before my battery started dying. Does anyone think this is just a looses terminal issue? Or maybe something leeching my power after the car is turned off?
Dirty connections never help. It is simple to clean with a wire brush (just don't breath the dust and I would recommend rubber gloves) and apply dielectric grease to try and prevent it from happening again. Then tighten till you can't move the clamp on the battery terminal.
power can remain on the cigarette lighter when you have the car off and the ignition off (that is the case with my Ford mondeo mk3) if thats the case and you leave a USB charger for your phone in the cigarette lighter, it can slowly consume power, causing your battery slowly deflates
It's possible your battery is shorting out internally..."won't hold a charge" This is more typical for a overnight/short time frame loss of charge. Any parts place can load test the battery.
For a couple of days or more loss of charge...When you turn off the key, the body control module goes through a electrical shutdown procedure. At minimum this takes several minutes. Worse case is it fails to shut down and drains your battery. This is a common problem on Fords. Cheapest fix is a manually operated battery disconnect switch at the negative battery cable. Body control modules are expensive.
Electrical connectors are simple...clean and tight.
