Dear all;
Wonder if any of the BR intellect can help me get to the bottom of this/
My 1999 Mondeo has the battery light dimly lit. The problem first appeared ahen my wife was driving the car at night on the long m-way journey. She stopped and called the RAC, but (Sod's law) the problem had cured itself by the time the patrol arrived. He checked the battery, charge voltage and belts and reported all appeared well. The next day I checked battery voltage (12.2V?) charge voltage (14.4V at idle and when revved) and took the car for a 30 mile drive and no light was eveident. for 2 days no problem, but yesterday the dim light re-appeared and hasn't gone away since.
Charge voltage reads 14.2V (was it really 14.4V before?) with no load. With all lights, heated screens and a/c on, the voltage drops to just over 12.
The only other bit of possibly relevant info, is that I have just had the 2nd (white) socket fitted to the towber. No idea how this could cause the fault tho!
Hoping for some ideas!
Thanks
Andy
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Not being a caravaner (yes!!! punches air in delight) is the white one the one used for charging and powering utlities in the caravan? If so the symptoms and the fitting are too close to be anything other than related.
If I am right about the white socket, where is this feed taken from? I would go straight to the battery, and remake (take off, clean, retighten) all the connections on it. And i would be having a word with the fitter who put it on.
If I am wrong about the white one being the utlity power then I am talking thro my botty.
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This could be one of two probs. A blown diode or a Slip ring Brush. The later is the most probable. How many miles has the car done 80K plus and I would go for a replacement brush pack particularly as the fault was initially intermittant. Also the light on and lossing a bit ot top end charge fits the bill. This brush fault can also cause the light to get brighter with rpm. Go to a local alternator recon shop and just buy a brush/regulator unit and fit as appropriate. Regards Peter
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This could be one of two probs. A blown diode or a Slip ring Brush. The later is the most probable. How many miles has the car done 80K plus and I would go for a replacement brush pack particularly as the fault was initially intermittant. Also the light on and lossing a bit ot top end charge fits the bill. This brush fault can also cause the light to get brighter with rpm. Go to a local alternator recon shop and just buy a brush/regulator unit and fit as appropriate. Regards Peter
82k miles. Can anyone advise me please how difficult and time consuming a brush change is (once I have extracted the alternator!) ?
Interesting what you say about the brightness. In spite of my reply to John S's post, when my wife originally had the problem, she did say that the light went off when she pulled off the motorway onto a slip road. Sounds a strong possibility.
THANKS ALL FOR YOUR HELP THUS FAR!
I'll try the simple ideas tonight
Andy
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Not being a caravaner (yes!!! punches air in delight)
I'm not either, though I have nothing in particular against them. However, I am guilty of having purchased an old 'van to do music festivals (Glasonbury et al) in relative comfort this summer!
is the white one the one used for charging and powering utlities in the caravan? If so the symptoms and the fitting are too close to be anything other than related.
Yes, correct
If I am right about the white socket, where is this feed taken from? I would go straight to the battery, and remake (take off, clean, retighten) all the connections on it. And i would be having a word with the fitter who put it on.
Sounds well worth a try, including kicking the fitter if that is the fault. If I am wrong about the white one being the utlity power then I am talking thro my botty.
It's OK, you're not. Thanks
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Andy
I'd expect a bit more than 12V even when fuly loaded. The intermittent nature of the fault makes me think the alternator brushes are on their last legs.
Regards
John S
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There was a service fix for this concern on the Escort TCI.The battery did not go flat but the alt. warning light glowed dimly.The fix was to remake the terminals on the alternator.It worked on my car.
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Andy I'd expect a bit more than 12V even when fuly loaded.
I was surprised how low it dropped too, made me think there really might be a fault. The Haynes suggested that I should get 13V+ even when fully loaded, if I increased the engine revs from idle. I was still slightly confused though, because the light is there, constantly dim all the time whether the voltage at battery is 12.5 or 14.4.
The intermittent nature of the fault makes me think the alternator brushes are on their last legs. Regards John S
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Asumming all connections are OK and the voltage is below 13.25 at 2500 then you have a prob. Once the alternator if off it is usually just two screws and the pack comes off and the new one on. Not done it on a Mondeo but go look at the reg/brush pack at your local service stockists or in a Mondeo manual. Regards Peter
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Peter;
Thanks for the advice. Will do that if the connections turn out to be OK
Andy
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Fitting of the supplementary tow socket may be the cause of the problem.Usually a split charge relay is used to power the 2nd socket,which is triggered by the alternator warning light.Excess current draw on this line could cause batt w/light to glow.you need to recheck your power pick ups.
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I know that there is a new relay on the inner wing and a new fused connection direct to the battery +ve. I have no idea what a split charge relay is though!
Would you be so kind as to explain about rechecking the power pickups in slightly more basic terms?
Thanks
Andy
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Thought I'd get back to basics. If the relay might be the cause of the problem, I'll take it out and see what is the result.
So I draw out all the connections so I know how where to put them back, then remove them all. Checking that I won't get any shorts, I ask the wife to start the engine. No battery light! So I reconnect the wires one by one and guess what. Still no light. Stop engine, restart, no light again.
So I know little if anything more than I did. I now plan to use the car again until the light re-lights and try removing the relay connections one-by one.
I'll update when I have any news, thanks again for the help.
Andy
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OK I have re read your postings again and now realise you have a split charger. Disconnect the wire from the alternator to the relay and check that out. It is not a very good idea to use the charge light feed to drive the split charge relay anyway as the relay pulls 150 to 200 ma and the feed from the alternator is only designed to feed 40 ma. There are plenty of switched feeds to choose from if you want to leave it connected. Ideally this relay should be controlled by a solid state differential comparator that only turn the split charge relay on when the main battery if above 13.75 volts, but that is a different story. Regards Peter
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