Roadsport06 Posted April 21, 2012 Share Posted April 21, 2012 Good evening all, I've just go back from the Aberdovey blat. I had the alternator light come on whilst on the motorway. I came off the motorway and since I didn't have a multimeter I called on my breakdown cover. The guy tested the alternator charing. The voltage was 14.4V so I was good to out across Wales to catch up with everyone at the Halt cafe. The guy said the alternator light staying on was likely to be my diode pack. I don't know my about alternators, I assumed the diode pack would be to give a DC supply. Is it likely to be the diode pack? My guess is it would be a feed from the alternator to the dash light. Before poking around what are people's thoughts? Where is the feed on the alternator for the dash light? Many thanks Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 21, 2012 Member Share Posted April 21, 2012 I'd poke around first... check those voltages yourself at the alternator terminal and at the indicator light. What sort of alternator? In another recent thread I realised I didn't understand the sort that have an additional terminal and lead... something to do with energising the photon warp field drive coil. Luckily someone else did. Have you changed anything under the bonnet in the recent past? Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 21, 2012 Member Share Posted April 21, 2012 PS: Alternator light saying on Most of us don't have that level of sophistication in our alternators! But I think the Morris Maestro Van Den Plas might have done. :-) Jonathan Link to comment Share on other sites More sharing options...
johnnyseven Posted April 21, 2012 Share Posted April 21, 2012 diode pack favorite---the ignition/charging light comes on on mine as soon as i connect the battery--if i disconnect the single ignition feed the light goes out--but its still charging battery--taking it to get it looked at on monday--i will post what they say the problem is Link to comment Share on other sites More sharing options...
Roadsport06 Posted April 21, 2012 Author Share Posted April 21, 2012 Very witty JK 😶🌫️ I should have said 2006 k-series. Nothing changed under the bonnet apart from a one way valve for the apollo tank. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 22, 2012 Member Share Posted April 22, 2012 I now think I understand even less than I did. How does a fault in the alternator diode pack cause 14.4V on the output and not extinguish the warning light? Does the lead to the light not come from the point that you're measuring the output voltage? Thanks Jonathan Link to comment Share on other sites More sharing options...
Roadsport06 Posted April 22, 2012 Author Share Posted April 22, 2012 Update, the immobiler light was off this morning and the battery giving only 1.3V. I had the Optimate connected all night so it was draining more than the optimate was giving. I've disconnected the battery and put it on charge. The diode pack didn't sound right to me, I think the RAC bloke just wanted to get off and so did I in order to get to the Halt cafe in time. I will check later that the alternator is still charging the battery and disconnect it again. Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 22, 2012 Share Posted April 22, 2012 bl00dy hell, that's one seriously flat battery. Are you sure its only 1.3V. I'd be tempted to say that you connected the charger the wrong way round except the Optimate is protected against that. The fault is likely to be the regulator which is probably what the RAC man meant. The warning light is controlled by the regulator in many modern alternators. If your battery really is that flat I doubt that the Optimate will charge it as it won't deliver enough current. Try and borrow a proper charger or get the car started with jump leads, if it will start at all, and charge from the engine. Watch the sparks when you connect the jump leads though. Link to comment Share on other sites More sharing options...
Roadsport06 Posted April 22, 2012 Author Share Posted April 22, 2012 Thanks Paul, I'll "look into" the regulator. Yes, when I went to the car and the immobiliser light wasn't flashing and the voltage across the battery being so low I was a bit shocked as this was 12 hours after the blat! However, after getting back home and taking off the bonnet I came back to the car 2 hours later and the alternator was still warm. I put it down to heat soak, but perhaps a reasonable current was going back from the battery to the alternator? I'll look at wiring diagrams later as I could well be talking out of my 🙆🏻. The battery has been on charge with a proper charger this morning and it is back on the optimate (not connected to the car). I've finally got around to ordering some lagging for the exhaust pipes too as the heat off this can't be good for the alternator and starter of a k series. Link to comment Share on other sites More sharing options...
tbird Posted April 22, 2012 Share Posted April 22, 2012 you are not talking oo 🙆🏻, if diode pack has blown diode you will have current flow back through Alternator, so could well be warm with very flat battery, Tim Link to comment Share on other sites More sharing options...
Area Representative skeetsy Posted April 22, 2012 Area Representative Share Posted April 22, 2012 Hmmm, a couple of thoughts.... My alternator light comes on occasionally and did so quite often when I got the car, initially I thought it was down to a dodgy connection within the loom at one of the connector blocks which is strapped to the diagonal brace below the inlet manifold (mine is a 2006 K series) as when I wiggled the block the light would often go out. However, since having purchased an Oxford Oximiser 900 and used it religiously the light rarely comes on now, only when I've been using the battery at bit for lights, so I'm thinking that perhaps the battery is not in great shape, or the alternator is charging only just enough. In terms of heat lagging for the exhaust primaries I was considering this, but having read various threads on Blatchat I decided against it - apparently the K series doesn't cope very well with the additional heat soak from the exhaust pipes which would normally just radiate away but is trapped by the lagging. All the best Richard Link to comment Share on other sites More sharing options...
Johnty Lyons Posted April 22, 2012 Share Posted April 22, 2012 How does a fault in the alternator diode pack cause 14.4V on the output and not extinguish the warning light? Does the lead to the light not come from the point that you're measuring the output voltage? Seperate Diode NOT the main rectifier diode pack catches a few folk out. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 22, 2012 Member Share Posted April 22, 2012 *arrowup* *arrowup*Certainly caught me out. I thank you. Jonathan Link to comment Share on other sites More sharing options...
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