I rebuilt my alternator yesterday with new brushes from Larry B. It was horrible blizzard conditions. Anyhow. Here is the description:

Truck starts fine. Even cold. runs fine. heater works, headlights not dim, all systems work. Turbo good, no lagging, 4WD good.

Here is the problem: GEN light comes on after about 200ft of driving. stays on. voltage meter in truck reads solid 10v. ***? I tested the batteries they are good. Alternator is good. All systems charging. What gives? Could I have fried my gauge when the alternator cable arced. I know I did not disconnect my battery. It was a blizzard. Do I need to get my computer flashed at the dealer? Or did I fry my gauge when the cable arced and my guage is telling my computer there is not a sufficent charge then my computer tells me my alternator is not working?

Any ideas?

 

It's possible that the big charge fuse in the PDC blew when the charge wire arced. If that happened, the alternator would still look like it is working, but the charge current wouldn't make it to the batteries.

 

Is the PDC the fuse box on the left wheel well. It seems alright but I will check and make sure.

 

You need to fill in signature [ giving details on your your truck is & mods ] .
Then use a multimeter to see if you are getting all the right volts every where , then if all is good , a load test [ this requires a special meter , measures high amps ] .
There is also a fuse box out under the hood .

 

From previous posts it looks like we are talking about a '96. Does the tach work when the voltage drops?

 

Yes, that's the Power Distribution Center. The charge fuse is screwed in, I think it's a 140 amp fuse. If you had a big arc when you removed the alternator, you probably popped that fuse.

 

yeah sory. It's a 96 2500 with a banks twin ram kit, that some previous idiot installed. well here is an update. I fixed the fuse 120 amp, yes it was blown. And... nothing. The same GEN light on no charge and now the snow has cleared up I realized I have no OD. I am really frusturated with this truck. any ideas. driving 40 mph to work with dim lights.

 

It sounds like a crank sensor problem. I ask again, does the tach work?

 

yeah the tac works. but... I think I saw my WIF and trans temp lights go on quickly. do the gauges have to not work in order for the crank sensor to be bad. I wonder if is needs a new alternator as possibly the diodes are bad.

 

It sounds like you may have fried your PCM or some of the wiring to it.
Always a good idea to disconnect the batteries when doing this kind of work to avoid problems.

 

the gen light was on before any of this and so was the flash of the WIF lights. however the charge issue and od were not.

 

what should i do now

 

Check for codes http://dodgeram.org/tech/dsl/trouble..._DTC_codes.htm

 

Unfortunately the codes on the 96 were pretty useless, so they may or may not tell you the ECM is fried. But it sure sounds like you did so by arcing a circuit.

With your alternator not being properly excited, and the OD on the blink, my suggestion is to do a search for a rebuilt ECM unless you want to try the voltage regulator conversion first.

Sometimes you can get away with just doing the voltage regulator conversion (search for the posts here, it is a common conversion and has been discussed at length), and usually when the voltage regulation function is removed from the ECM the OD will come back alive when the ECM quits seeking a ground through the alternator field. But, not always!