Generator/charging
 

Hey everybody,
I need some information on how the chargingsystem works on a C124 - 230CE. I reasently changed my alternator bacause the old one gave op. After I changed it I discovered that it only delevers 13,5 volt with all acc. turned of, and just above 12 volt with everything on. This is no matter the RPM of the engine. Just today I got the oppotunity to measure this on a W124.... 14,4Volt in idle whit the lights on.... In addition to this I have a problem with the bulb warning light. I have checked all bulbs, and everyone is working perfect. If I look at the wirering digram I can see that there is a blue wire going directly from the alternator to the light control unit. I guess that this wire is the "field" for the alternator? If so could it be the light control unit that is faulty? I hope anyone have som experience on this. I have checked the ground from engine and headlights, and they seems to be ok.

With kind regards
Jakob

The big question on this one is where did the rebuilt alternator come from (I assume it is rebuilt) and what was wrong with the old one. If you had a complete failure on the old one that is one thing. However you may have never actually tested it like you are with the new one. Lower voltages can be systematic evidence that there are either cable problems or poor battery connections or maginal battery but is most likely a marginal alternator. Have it load tested to see how many amps it delivers by the place that you bought it and see what they say.