Chrysler Repair: Code 41, field windings, caravan 2

Question
Finston;
 We have a 90' caravan 2.5L with Turbo. We keep getting Code 41 (Alternator field not switching properly). We ahve replaced the Alternator and have cleaned every connections that can be cleaned and even tried disconnecting the Neg.battery Terminal for over 10 Minutes and still get Code 41.Could you please help?
                                 Thank You;
                                    Vick

Answer
Hi Vick,
How did the cooling system project of a little while ago turn out?
The 41 code is fairly straightforward. It says that the alternator is not putting out current when asked to do so by the field coils being activated while the engine is running. Ther are four posts on the alternator with a plug that pretty much assures the proper connections will be made. aThe J2 and R3 posts of the alternator, which both have dark green wires attached to them are the two ends of the field windings of the alternator. These run to a 10 wire disconnect near the battery and one of these wires changes color, with the dark blue/yellow going to the downstream side of fuse #16 which is hot in the run position of the ignition switch and the other wire remains dark green and goes to terminal pin 20 of the engine controller 60-way plug. It appears to me that one of the field posts, the J2 post of the alternator, is supposed to show 12v when you have the ingition in the run position. It also appears to me that the R3 post when the engine is running should show either 12v contantly (when the alternator is not being asked to put out any current) or its voltage should oscillate rapidly so as to put some average lower voltage on the other end of the coil and thus produce a current output at around 14v potential on the black/gray output wire at post R6 of the alternator that is attached to the +  post of the battery and so this is the source of the charging current. Have you checked all those wires for continuity between the alternator and their respective endpoints using a continuity checker or and ohmmeter (the last post, R9, should have a black wire that is grounded on the engine and the alternator case).
If all those wires prove to be connected and still you don't get any charging voltage I would suspect that the engine controller is bad. If you are getting voltage and the battery is charging then the 41 code is false.
So let me know what is the status of the charging system and what you read as to the voltages on the two posts of the field coil connections (those are the side by side posts at the alternator harness plug-in) and the output voltage of the alternator.
Roland