Jump to content
Do Not Sell My Personal Information

KA 2004 1.3 Duratec. Alternator Charging light on


Recommended Posts


The charging warning light has been on for many months.  battery still charges and car starts first time, every time, so I assumed it was the 'broken wire in alternator connector' issue that a few posts have mentioned on here.

Bought a replacement connector (new connector with 3 wires already connected) and did a perfect job of cutting off the old connector and soldering on the wires of the new connector.  Each wire protected with new heat shrink insulation as well as being taped.

Result:- light still on.

I examined new connector and wires and every thing looks perfect.  I must admit I was surprised not to see any lose connections in the old switch I cut off ... I just assumed it had broken internally.

Anyone have any idea what the problem is?

Alternator still charging fine ... just that annoying light on.  I assume if the alternator ever does stop charging I won't know about it (as light always on) ... that is until battery starts to go flat!!

Any suggestions appreciated.


  • Like 1
Link to comment
Share on other sites

Sounds like the fault is either in the alternator (could just be bad solder joint on the connector, or something more complex), or just possibly in the PCM or even the instrument cluster (IC).

The monitoring wire from that plug goes to the PCM (engine computer) on my car, and PCM then informs the IC over the CAN bus.

As all this is a bit complex, and may be expensive & hard to fix, if the car works ok, just get a cigar lighter (power outlet) plug in voltmeter. Pretty cheap off Ebay/Amazon. Then you can keep an eye on battery volts, you'll easily see if it is not charging, once you get used to the readings (>14v on charge, <12.5v on discharge)


  • Like 1
Link to comment
Share on other sites

Check the belt tension first.

Check your earth connections as well.

Simple stuff first.

The cigar socket volts tester is always a good idea to have in the car.


Sounds like a faulty diode in the alternator though!

If the battery light is on without ignition on then the alternator diode is shorted out and you will need a new diode pack.


Link to comment
Share on other sites

It's very likely to be the diode. I replaced with a second hand eBay one and the battery light came on immediately Swapped it for a quintin- hazel new one for£85 and the light went out. 

It needs swapping, also if it's overloaded it could smoke or worse catch fire. It might give you a small charge to battery but not enough to convince Cpu that it's correct. Go to Motorland and order a new quintin hazel model. Don't recommend a second hand one.

Link to comment
Share on other sites

On 20/06/2016 at 6:29 PM, james2747 said:

The charging warning light has been on for many months.


7 minutes ago, andybadcats said:

Swapped it for a quintin- hazel new one for£85 and the light went out. 

The advice from Andrew is good, assuming you can do the job yourself. But changing alternators on small, modern cars can be quite difficult. Garage labour costs might double that bill. And there is a small chance the fault could lie elsewhere, in the harness, or connector at the other end.

It would be a good idea to check the temperature of the unit after a decent run. (Carefully!). If hot enough to boil water, it is too hot. But if has worked for months, there does not seem to be a drastic problem, at least not yet.

It is your choice really, depending on finances & your use of the car.


Link to comment
Share on other sites

If you take the diode pack off its extremely easy to test the diodes if you have a basic multimeter and if you have the soldering knowledge you can buy the diodes off eBay for 5p each and save yourself quite a few quid - 20p or £100? Up to you!


Link to comment
Share on other sites

Latest Deals

Ford UK Shop for genuine Ford parts & accessories

Disclaimer: As the club is an eBay Partner, The club may be compensated if you make a purchase via the club

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...