Many times when the alt stops working , the contacts at the plug get corroded. Have you been able to try removing and reinstalling the plus a few times to make sure the contacts are good?

 

I'll give that a try....thanks

 

I stopped by PASCO ( a regional chain store that specializes in batteries, alternators and starters) where I bought my battery less than a year ago. They hooked up their charging system diag machine and my alternator passed all the tests. the charging volts and amps were on the mark at idle and at high RPM and with a heavy simulated load. Yet, 2 days later I'm on the side of the road. It died while driving down the road and was too dead to re-start. I have done some digging and have found that this particular model ( 2002 Taurus SEL with DOHC ) uses an alternator that is regulated by the PCM. It also requires that you either remove the crank pulley ( for access) or separate the ball joint and drop the "A" frame just to do R & R on the alternator.

I'm missing my 67 plymouth more every day.

 

They had enough room under the hood to curl up and go to sleep in there,Huh?

Bill before you get too involved with possibly removing the alternator , if you were contemplating that, can you fill in some blanks on the tests the place did on your vehicle's charging system ? There is a fuzzy portion from what you explained and maybe we can save you some addl work.
As you know alternators can be troublesome and work intermittently. AND so can batteries.
What checks were you able to do when you got the vehicle back home?
Were the checks done after you got the car restarted?
If I recall correctly you have a voltmeter available and just maybe you can run a few checks unless you already fixed the problem.
It's very unusual for a charging system to pass all the usual tests and crap out a day later. What connections have you checked?

 

The day it died I sat there for about 10-15 mins and tried to crank it and although slow it cranked and started. I was only about a mile from home so I made the attempt and got there. I backed into the driveway and shut it off and tried to re-start and it was too dead to start. I hooked up the battery charger and have been doing that every night to be on the safe side so I can be sure to have enough battery to to work and back. I have almost a 100 mile round trip. With the snow and the cold and other obligations I haven't checked anything yet. Just putting it on charge every night. It's like I have an electric car!!!!

What's really odd is that my battery light has not come on at all, even the night it died in it's tracks. The light works, it comes on when the key is turned on for the lamp check. Something I am wondering is, since the regulator is controlled by the PCM, are there any OBDII codes related to the charging system that I could check for? The only evidence I have when I'm not charging is at night when the headlights are on. When It is not charging they are significantly dim. I did make a stab at checking the plug on the alternator but I could not get to it from the top side or even see it for that matter. I haven't had the gumption to get the car up in the air with all this snow and ice in the driveway. I'm damn near 60 years old and laying under a car in sub-freezing weather on frozen ground is really loosing it's appeal ( not that laying under a car ever did really have any appeal but at least a few decades ago it was more tolerable )
So, anyway.... what tests were you going to suggest?

 

We need to know if the plug on the alt is making good contact with it's contacts on the alt. Then make sure the output wire from the alt is making a good connection from the alt to the battery positive terminal. It also supplies the power distribution block under the hood. If the alt is putting out 2 amps the lite will not come on since it still is charging something. The volt reading at the battery should be the same as that output wire coming out of the alt,is it? Are you using a digital meter, should be ! Check that reading at the alt and every connection from the alt through every connection on the way to the battery positive post. With the engine running you should get at least 14 volts at idle at the battery. This is all basic stuff and includes checking all the ground connections too. If the readings are in the ball park, check them again with the headlights on and blower motor going too , that loads the charging system and it should be able to hold the 14 volts. Let us know what you get with these checks.

 

I haven't checked anything yet myself. but the shop checked and it was charging at 14 volts at idle and at 2000 rpm and with a simulated load as well as with the lights and blower on. It was around 30 amps at idle and 99 amps at 2000 rpm with a simulated load. That's what is so frustating. Everything seems ok but it still dies..

 

It is possible the system is intermittent and that is why I suggested you do those tests yourself. If the system is working as it should and the engine is shutting down AND just about cranks over , we need to know what the available voltage is at the battery at the time it doesn't have enough power to crank the engine over. The system needs electrical power to run and if it isn't available it will stop running . If the available voltage at the battery is 12+ volts and the engine will still not crank over to start there is a big voltage drop somewhere and if that is the problem we can go from there. From what you tell us you have no problem getting the engine started after leaving the charger on all nite ,correct?
Also , the vehicle sets X number of hours until you are going home and it still starts OK,is this correct?
The problem shows up after driving a while on the way home , headlights on yes ,no, and eventually shuts down , but you are still able to get it started , barely , is this correct?
Just because it checked out when you had it checked doesn't mean there isn't a problem in the system.
What I would do in a case like this is let it run with the same conditions as when driving home and keep an eye on the system voltage and if the same thing happens you will be able to catch it there in the driveway.