mercedes alternator

Hello i have a 2001 mercedes w203 2.2 cdi and i been having problems with the visit workshop/battery warning message. First time it came up, battery was getting 14,5 volts and no alternating current was getting there. Alternator was removed, and this is a big pain in the rear since its on a bad spot and its watercooled (delphi 190 A). Fitted a new regulator and brushes, since the original brushes were almost on the limit.
Still same problem. Regulator was aftermarket since no original is sold, mercedes only sells the entire unit.
I tried another alternator. Same problem. I continued using the car to the point it now does not charge the battery, all i can get is 12, 2 or 12,3 when engine is running, still no alternating current getting to the battery. I didnt want to take the alternator out if it has no problem, I am asking if anyone here can help me find the 2 wires on the ECU loom so i can pinch them and read any ecu signal, if any and determine if its either the alternator, wiring or ecu problem.
Paul, care to give some hint?


by the way, we have no place to take an anternator like this to get tested. the 2 wire plug has an L and DFM wire

Hi,

I'm not an expert and can't do that much to help you but I can clarify few things for you.


- There shouldn't be any alternating current going to the battery, that is why the alternator has an internal rectifier.

- DFM stands for "dynamo field monitor", it is a PWM (pulse width monitor) signal that is used to notify other ECU's of the alternator capacity utilization.

- L stands for the lamp connection (charge warning lamp).

kouKiJu wrote: There shouldn't be any alternating current going to the battery, that is why the alternator has an internal rectifier.
.

Yes i didnt explain it completely: no Ac detected may be an indicator my diodes are good, still does not garantee that is not the problem. I suspected this all happened when a friend helping fitted the battery. I cannot be sure if even briefly the terminals made contact on the wrong side. Maybe my regulator is bad. Maybe the new one i tried was bad too. Kinda strange but i just didnt want to take the alternator out if its not the culprit. I know the DFM wire carries a digital signal from the ecu. i dont know if the alternator is even getting that signal, and i dont know also if i can try to shunt this dfm at the plug to excite the alternator and make it charge the battery, like Paul did here :

Ok, cool. Someone correct me if I'm wrong but I believe that the DFM wire can be an excitation for the alternator, or it can be just an input of alternator capacity utilizatin for other ECU's. In the case of self exciting alternator it is the latter.

This link explains a little bit. Be sure to know which type you have in your car. I want to make a note that what I'm saying here is based mainly on book learning, not so much on field experience.

eblogbd.com/details-of-excitation-system-of-alternator/

I guess this is not the problem but have you a fully charged battery? Is battery fully functionally.

yes i have tried other battery, diagnose machines cant find anything ( at least none so far)

could anyone be so kind to tell me if i could eliminate the inside regulator and run some wires onto an external universal regulator? so that the battery and alternator can work together detached from anything else? I do not need help on wiring this, i just dont know if this delphi alternator and its exciting coils are compatible with this kind of operation. Its my car and i am very tired of spending money , i dont care if any error still comes up on the dash i just want it running and ready when i need it.
Id really appreciate some more help, thanks

Has anyone used one of these? Will the field replacement module work on my car?

DODGE-EXTERNAL-REGULATOR-KIT-HEAVY-DUTY-ADJUSTABLE-VOLTAGE-REGULATOR/