Focus 2012 battery light
Discussion
I keep getting an intermittent battery warning light up which can disappear within minutes or stay on for longer.
Not long ago it was happening a lot and despite the car starting fine one day the battery died halfway through a drive, lost power steering etc and wouldn’t start again.
Put a new battery on and it’s better but still happens. Have had a meter on when the engines running and it seems to be charging. Any thoughts welcome?
Not long ago it was happening a lot and despite the car starting fine one day the battery died halfway through a drive, lost power steering etc and wouldn’t start again.
Put a new battery on and it’s better but still happens. Have had a meter on when the engines running and it seems to be charging. Any thoughts welcome?
I checked the battery voltage with the engine off and then checked it again with the engine running and there was an increase, which led me to believe the alternator was putting a voltage on the battery. However - this was when the battery light wasn’t lit as with it being intermittent it’s hard to replicate.
Think the suggestion of keeping the meter in the car and keeping an eye out for the battery light is a good idea.
Think the suggestion of keeping the meter in the car and keeping an eye out for the battery light is a good idea.
If it's an intermittent problem, you need to investigate while it's happening.
The warning lamp usually indicates that the battery is not at the same voltage as the alternator output. That might be because the alternator output is too high or low, but could be because the battery isn't connected to it. I've seen fusible links fail mechanically due to vibration and fatigue initially produce this type of intermittent problem - or it could be any other wiring fault.
The volt meter tests other suggested would tell you what sort of problem you're facing and it should be simple to pin it down from there.
The warning lamp usually indicates that the battery is not at the same voltage as the alternator output. That might be because the alternator output is too high or low, but could be because the battery isn't connected to it. I've seen fusible links fail mechanically due to vibration and fatigue initially produce this type of intermittent problem - or it could be any other wiring fault.
The volt meter tests other suggested would tell you what sort of problem you're facing and it should be simple to pin it down from there.
foxbody-87 said:
I checked the battery voltage with the engine off and then checked it again with the engine running and there was an increase, which led me to believe the alternator was putting a voltage on the battery. However - this was when the battery light wasn’t lit as with it being intermittent it’s hard to replicate.
Think the suggestion of keeping the meter in the car and keeping an eye out for the battery light is a good idea.
Can you be more specific, it makes a HUGE difference?Think the suggestion of keeping the meter in the car and keeping an eye out for the battery light is a good idea.
As in what voltage did you get with the engine off & then with it running.
E-bmw said:
Can you be more specific, it makes a HUGE difference?
As in what voltage did you get with the engine off & then with it running.
Sorry, I can’t remember now other than it was about a 2 volt difference. I’ll measure it again when I’ve got my meter with me (it’s currently in my work bag and I’m on leave As in what voltage did you get with the engine off & then with it running.
)I had a similar problem on a 2009 1.6 TDCI - intermittent battery light when running. It's a lot easier to see what's going on if you have a Ford specific scan tool like Forscan. If you have access to same, it's worth looking for stored DTCs, and also the live data. Otherwise, the voltage at the battery when the light is on and off can give a good clue as to what's going on. 13.5V or thereabouts often means the ECU, which controls the regulation on these, has lost communication, so it defaults to a 'safe' running value, which will eventually lead to a flat battery.
If that's the case, but you get nearer 14.5V when the light isn't on, try testing to see if you can load it with heated screen and headlights and see if the light stays off with the extra load. If it does, and it maintains close to 14.5V despite the load, that suggests the guts of the alternator itself is OK, otherwise it wouldn't be able to supply the extra current to maintain the voltage.
In which case I'd start by paying a lot of attention to the alternator connector, or 'pigtail'. Wires have been known to break near the connector, but just as often the connector itself doesn't make proper contact on all pins all the time. Repair sections are cheap and easily available.
If it's not that, it could be lots of other things, but you'd then you'd really need a decent scan tool like Forscan so you can see what the ECU can see.
If that's the case, but you get nearer 14.5V when the light isn't on, try testing to see if you can load it with heated screen and headlights and see if the light stays off with the extra load. If it does, and it maintains close to 14.5V despite the load, that suggests the guts of the alternator itself is OK, otherwise it wouldn't be able to supply the extra current to maintain the voltage.
In which case I'd start by paying a lot of attention to the alternator connector, or 'pigtail'. Wires have been known to break near the connector, but just as often the connector itself doesn't make proper contact on all pins all the time. Repair sections are cheap and easily available.
If it's not that, it could be lots of other things, but you'd then you'd really need a decent scan tool like Forscan so you can see what the ECU can see.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff