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Marksskagit

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marksskagit

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Have 2000 KAD43 diesel, looking for alternator wiring schematic, the proplem is all the warning lights come on when the ign. switch is turned on ( good:) ) but once the engine is started, the oil pressure and battery light glow faintly for about 15 seconds, then the battery light lights up and the warning buzzer sounds:mad:. All three batterys are charged, the alternator was checked out as good, seem to have all wiring tight and clean, but only get 12.6 v on the main battery,at idle or 1000 rpm. Looking for schematic with wire colors and placement to check things better:confused:*Any help MOST Appreciated.
Thanks
 
Some alternators need to be excited before starting to charge. The engine must rev above a certain RPM for the alternator to put out. Try reving the engine and then checking output.
 
Can't help with the diagrams, but check the voltage at the exciter lead. Some alternators have a switch of some sort (oil pressure, relay etc) that only feeds 12v to the exciter lead once the engine is running. Stops the exciter coil being activated when the ignition is turned on but the engine not running. Do you get higher voltages from the alternator with the engine running at higher rpms?
 
I think the battery light is the start of the exciter circuit, when the ing. switch is turned on voltage goes through the battery warning light to the exciter lead of the alternator,(not 100% sure) but the charging system seems to start right away, then about 15 sec. or so, the warning light comes on bright, and buzzer sounds. I'm thinking its the voltage regulator not letting the alternator produce more than battery voltage. The shop said that the alternator was OK but I didn't ask what its output was. Going to give this a try on my days off, and no I don't see an increase in voltage with higher rpm's which leads me to think its the regulator again.
 
Probably not feeding the exciter through the light. Could be, but sounds wrong. Can you put a volt meter on the alternator leads? If you can, measure the voltage between the earth and +12v with the engine idling and then again with the engine up at higher rpm's (say 2000rpm or so). If it isn't changing and going above ~12.6v, you are probably just looking at the battery voltage. Next try measuring between earth and the exciter terminal. This should have +12v on it once the engine is running. If it hasn't, then this is what you need to look at first. If it has, but there is no alternator output, the shop should have seen this when they tested the alternator.
 
Super cleaned all connections at alternator,put muffs on and started engine, with the same problem, so decided to jump the alt. + (red) with the field connection (brn) and bingo the light went off, volt meter in cab read 14.5 V, measured voltage at battery 14.2 slowly climbing to 14.4 V Stopped and started a couple of times and everything is good:eek: Oh I love electricity ! ! Thanks for everyones input.
 
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