also you may have seen this post about using a fused jumper?
https://www.ford-trucks.com/forums/6...-are-they.html

 

@annaleigh Thanks for the links. I ordered the 2003 electrical wiring manual to ensure that I test the system properly. My alternator troubles started after I drove over a poorly marked drainage ditch on a paved road in the Nevada desert. The positive battery cable flew off. The vehicle was running off alternator only for 60 plus miles until I discovered the disconnect an hour later.

I parked the van for nearly 3 weeks after this incident and noticed the battery was not charging. I am hopeful that it's something simple.

O'Reilly's bench tested the old alternator and said that it failed. I don't trust the results as they are as good as the person running the test equipment. What if I condemned a good alternator for .10 fuse?

 

did you order just the electrical manual or is it a EVTM? I have the Ford service manual on CD, EVTM, and a 4 or 5 page set of wiring diagrams. The wiring diagrams are like blueprints of the electrical system while the EVTM is geared more towards service and complements the service manual. Being a 2003 I am sure your electrical is much more complex then my 88!

I wonder if the positive cable shorted out against anything? You also have a separate system for your house batteries. Is there anything in that setup that might cause an issue?

I was thinking about your post using a jumper to provide 12 volts to the regulator. You can do that with the harness unplugged and then check the output voltage on the large cable? That way nothing would feedback into anything.

Yes that like/hate relationship with the parts store! My brake booster hisses a little when the peddle is depressed so I started looking for a new booster but there are none available. I ordered mine from O'Reilly's because,,, it has a limited lifetime warranty. It is a reman from Cardone. RA sells the same one but said it was out of stock. NAPA's part number is the same as the Cardone one O'Reilly's sells except for one different letter so i am pretty positive they are all coming from the same supplier. i am not going to return my core though. There are one or two shops across the country the specialize in rebuilding boosters mainly for classic cars but they will rebuild them up into the early 90's

Interesting thought abut cores... The video about the boosters, they will pay you for old boosters. Seems when cars are crushed the boosters are one of the parts that gets crushed to and so cores are starting to be in short supply for some classic cares.. I would imagine that is true about many other hard to find rebuildable parts also..

 

"did you order just the electrical manual or is it a EVTM? I have the Ford service manual on CD, EVTM, and a 4 or 5 page set of wiring diagrams. The wiring diagrams are like blueprints of the electrical system while the EVTM is geared more towards service and complements the service manual. Being a 2003 I am sure your electrical is much more complex then my 88!

I bought this manual.



I wonder if the positive cable shorted out against anything? You also have a separate system for your house batteries. Is there anything in that setup that might cause an issue?

There's chance the positive cable shorted something (old alternator) as the alternator was producing power for an hour. I assume the battery cable positive remains hot with the alternator running.

I was thinking about your post using a jumper to provide 12 volts to the regulator. You can do that with the harness unplugged and then check the output voltage on the large cable? That way nothing would feedback into anything." What larger cable are you referring to?

The post that you linked to suggests doing this: With the engine off, connect a fused (15A) jumper wire between the generator C102a pin I, circuit 904 (LG/RD), harness side and ground.
Is the charging system warning indicator lamp illuminated? Seems like a good elimination test.

 

I should have said the the wire going to the starter relay or battery.

Here is some info that might be helpful also.. Even though it is a crown vic the main basic alternator should work the same or be similar, maybe enough to help some till you get the diagrams..


https://www.crownvic.net/ubbthreads/...Number=2023263

Exerts
In the 1992-2002 crownvics, you need to connect the charge indicator bulb circuit on the instrument cluster to the alternator regulator in order to have the alternator charge.

It's really rare to see a charge indicator light fail on the dashboard. But if it does happen and you don't have a resistor in parallel with the charge indicator light, you can end up with an alternator that won't charge. This can be really frustrating for the vehicle owner. In such a situation, the vehicle's owner will have their car towed to a repair shop, the repair shop will note that the alternator isn't charging after charging the battery with an external charger enough to start the car and then connecting a voltmeter to the battery terminals while the car is running. The repair shop will replace your alternator only to find the new alternator still doesn't charge. So the repair shop will likely figure that they just got a "bad" alternator and have the parts store send over another alternator to install. But after installing the second alternator, the repair shop will find the charging system still doesn't work right. Maybe the repair shop will request another alternator from the parts store at this point, or maybe they'll suspect that something is wrong with the vehicle's electrical harness and start troubleshooting your car's electrical harness. Either way, you can end up with your car off the road for a while and incur significant labor costs over a two dollar light bulb.

 

@annaleigh Thanks for the insight on repair shops. Likewise, I was too quick to condemn the alternator. I stopped after replacing 1 alternator. My problem was simple and self-induced. I installed a kill switch activated by a relay. I tapped into the instrument cluster battery indicator 5 amp fuse for 12 volts KO power. I did not know that this affects the voltage regulator. I need to dig deeper and learn why this is not a good idea.

The link you provided sending me to the 3G alternator is the same diagram that saved my butt from ripping out the alternator again. Pin #1 (battery indicator, control) should have had 12 volts with KO. This lead me to the fuse diagram that showing that I tapped into the battery indicator circuit! I think I blew over $300 for the new alternator, new VR, relay, and kill switch.




I disconnected the kill switch and removed the fuse tap. My new 130 amp alternator is producing over 14 volts. I learned so much about alternators and electrical wiring. Thank God I did not install the kill switch prior to our 5-week family camping trip.

I plan on testing the condemned alternator at AutoZone as O'Reilly's said it failed.
​​​@JWA always says to get the correct manual. I ordered the Ford Electrical Wiring diagram manual.
@annaleigh Did you mention that there other detailed electrical manuals?




Thank you all for helping with this alternator problem.