perryqhill

Hello, a friend has a 04 Ford Ka and his battery light is staying on. He recently replaced the battery in an attempt to cure it, but to no avail.

Today I had a look and with a multimeter I got around 13.08v when the car wasn't running and 13.50v when the car was running - can anyone shed any light as to why the battery light may be coming on?

jansvans

hello

alternator not charging (faulty ) should be charging battery when car is running and producing up to 14.5 volts

look for a small blue wire on the alternator and make sure it has not broken or come off the alternator that is the wire that connects to the battery light in dash, as when engine is running current goes up the blue wire and to stop the battery bulb ignition switched current going to earth and hense the light goes out

hope that makes sense

tabetha

The fact that the alternator is charging shown by the voltage going up when running, shows that the thin wire, normally blue is connecting correctly, this is further shown by the fact it iluminates at all.
What you have is a defective DIODE pack with leaky diode's, which are like one way electrical valves, they are part of the regulator/rectifier part that converts AC current of the alternator to DC current which the car runs on.
A simple repair/replace will sort it, should be around £35/45, if removing fitting yourself which is easy on these.
tabetha

perryqhill

Long time no post - could you be a bit more specific on this, is it part of the alternator/where is it situated?

B19 JUB

i would have to say its got a broken wire at the alternator as these are so common and working for ford they do a replacement connector and tiny part of loom so it can be replaced.ill get the finis code for it for tomorrow if not fixed.alternator is located on drivers side of engine compartment.if can be seen from the front with bonnet up as there is a gap on the indicator part of the headlight.

the fact the battery is showing 13 or so volts is due to the smart charge system going into back up mode and causing the engine ecu to default to this voltage as it cant see an output from the alternator

hope that piece of waffle helps

tabetha

The FACT that the voltage raises when running show it to be charging, the light can still come on when charging, although of course it points to a fault as it shouldn't.

tabetha

B19 JUB

could it be the 13volts as he described is just battery voltage then defaulting as fault is recognised by ecu after engine is switched on?might well be a phantom fault but all experience should be welcomed and not shouted down with words in caps

typical.the one time i post on here possibly giving advice i get told off.i guess ill be a voyeur user again in future

coss1e2000

There is a small 3 amp fuse on top of the fuse box which is there to protect the PCM. This fuse sometimes pops and causes the battery light to come on.

You have to drop the fuse box right down. There's two or three fuses on top. If you check the small 3 amp one there's a good chance it will have blown. Worth checking before you fork out for an alternator

perryqhill

Cheers for the replies guys, I'll get onto him and mention this

trev1964

I dont suppose you got that finis code did you bud...?

palkj

Ka 2007 battery light problem fixed very easily and very cheaply thanks to posts found on various web forums! The battery light was coming on about 10 seconds after every engine start, and was then staying on. I checked the small 3 pin plug on the alternator, and the blue wire had corroded through. It took an auto electrician 15 minutes to remove the plug and reconnect the wires using 3 mini connectors. If I had not been proactive, this could have ended up expensive….as in a mechanic probably fitting a new alternator!