Engine/Transmission (1998.5 - 2002) Low Voltage

[RobertBradford]

1998. 5 (24 valve) Dodge Ram 3500



On the way home last night the warning alarm went off and I found the voltage at 12 where it normally runs around 14. I scan and got code 1682, Charging system voltage low. Sure enough I tested power at the battery before running the truck, 12. 2 and started the truck and got 12. 1. Thinking it was the alternator I sent the morning replacing it but the problem still exist. Now I'm at the point it may be the voltage regulator in the PCM.



Is there any way to test this before I send it to the shop and spend some big money??

 

[JMLambert]

I had this problem, it was the main fuse from the alternator in the fuse panel under the hood was blown. If this is the issue I could only find it at a Dodge dealer. This is an easy check prior to getting further into it.

 

[rkressg]

You can get a set of brushes for the Denso alt for about $15 at any Alternator rebuild shop. I know that you can also get these brushes from NAPA, but you will need to look in the catalog in the store, they are not in their computer (I believe in the Echlin book).

The Denso alternators are high quality, and very rarely fail to a point where they need replaced, but can usually be rebuilt and have the life extended for another 200k (they are expensive, even for a rebuilt unit).

With 270k miles, the brushes are probably worn down and are shorting out.

The brushes take about 20 min to change, and are very easy to get in/out.

If it is not the alternator fuse, or brushes, it could be the PCM, as this serves as the voltage regulator.

 

[RobertBradford]

THANKS... . It was the fuse. I forgot that it was there and sure enough it was blown. And you are right there are only two places to get one... The dealer, and he only had one in stock... and e-bay. So I bought the one from the dealer and bought another on e-bay for the bunee-box.



The old truck is back on line and the new alternator is making power. Thanks again