So im driving down the road yesterday and my battery light comes on. I stoped and pulled one of the terminals off and sure enough my van shut off. I know 99% of the time its the voltage regulator inside the alternator that goes bad. There isnt a whole lot else that can go bad but as it turns out my van has no regulator, the pcm controls the charging system so if it is the pcm that is bad im thinking I should be able to run a wire directly from the altenator to the battery and it should charge right, it just wont ever stop charging? Can somebody tell me if what im thinking is correct?

 

can u say .. module failure .. the pcm is the controller for alternator for a specific reason!! The battery is a capaciter for alternator current when the vehicle is running. The pcm will turn off the alternator when demand is such that excess a/c volts cannot pass thru and damage modules (ie: turning in tight corners when p/s demand is high and a/c compressor is on).. see what I mean.. excess a/c current that may pass thru the battery is alot like a lightning strike to your home TV.. Better to field the alternator and check alternator before condemning pcm. But running a direct wire .. Not recommended !!

 

I dont plan on running it like that, im talking about just to test it and make sure its the alternator. I understand that it cant be run like that. I just want to know if it will work for testing it?

 

No .., Can damage Pcm circuit .. If you can't field it, take the alt to local parts store, most will test for $0.00 !!

 

Took it off and had it tested and it's definitely the alternator but without a regulator what else can go bad? There's no play in the shaft so I'm sure it's not the bearings. I mean u spin a magnet in the presence of a coil and u make electricity. What could fail suddenly? It didn't slowly go out, it went out suddenly. I just hate to spend $200 if it's something simple

 

Brushes stopped working? Problem with the coil/stator? Lots of potential problems that can fail an alternator. Always remember, stuff was working before it broke. At some point X it stopped working and with electrical stuff, it's often "digital" works/doesn't work.

I went out to use the back bathroom at our house the other night and the light switch didn't work. Brand new switch less than 2 years old and it just crapped out when I hit it.

If you want a junker alternator for parts let me know. I just took one off our 06 because of the decoupler pulley so I have a spare with 75k miles on it that works fine.

 

Thanks for the help 06caravan. I took the end cap/cover off the alternator and I discovered that where the coil wire daylights out of the alternator and jumps over to the next coil that one of them appears to have gotten hot and separated from where it's suppose to connect. I just uses a piece of wire and jumped it over to the next coil. Now I'm getting voltage at each coil but for some reason I get no voltage at the terminol. Granted I'm spinning it by hand but I'm definitely getting a small amount of voltage at the coils.

 

No problem! Glad you were able to get it partially sorted out. Figured something had popped and stopped working. Last alternator I rebuilt fully was for a 60-something Cadillac. With work and kids, it's so much easier for me just to swap out with new parts anymore, even if it costs more.

Hence the good alternator with a bad decoupler pulley in my basement. Someday I'll put a pulley on it and use it but at the time I had to get it running again.

Do you think perhaps there is an internal wire that has also melted or shorted that is causing the issue?