ICQ>

Dan,

In response to your question probably not.

The D+/61 wire supplies current to "jump start" the alternator with a magnetic field when none is present. On an alternator that is in service and has been running ok, there is usually enough residual magnatisim to cause the alternator to self excite. I have had many cars where the customer complaint is "no dash warning lights" The car ran and charged fine but the D+ wire was disconnected.

On the other hand if the large red wire (positive) or the blue (negitive) wire were to come off the alternator the charging will stop right now! (you no longer have a complete circuit.

As far as your question about the battery, you could have just a bad battery with a good alternator (happens, but usually a battery failure gives some warning) or it could be an alternator failure. Remember this the alternator is designed to keep a fully charged battery fully charged or to bring a mostly charged battery up to full charge, it is not designed to charge a dead battery. This is due to the fact that the charge rate is only a few amps above what the car requires to run.

Now if it were me in your position here is what I would do. I would take a battery with me (buy, beg, or steal). I would install the battery and check the charging voltage as I described in my first post. If it is between 13.5 and 14.5 with the engine running and the light on, recycle the old battery and it's pizza and beer time. if it is outside of that range replace the alternator, then move on to the pizza and beer.

If you think the battery that went dead is saveable charge it prior to reinstalling it.

For peace of mind you may want to visit a mechanic and have him check the charging system output. some place will do it for free others will charge as much as one hour for this service. (but hey when you consider how much a tow bill and the hassle is, one hour labor is pretty cheap!)

Hope this helps