Changing The Alternator
 

I just got my van today. Its a 1989 Dodge RAM 2500 Conversion with the 318 engine. It was hauled here on a trailer, and supposedly only needs an alternator and some wiring fixed. The lady I got it from said her son got drunk when he put the new alternator on and shorted something. I'm going to try and track down what caused it, so the first thing I need to know is the PROPER way to replace the alternator.

I took the alternator up to Advance Auto Parts; they looked it up and identified it as a "Nindispenso" (sp?). One of her neighbors offered to sell me an alternator from their truck, a 1995 Dodge RAM 2500. According to Advance, both alternators look exactly the same except for the type of pulley; this shouldn't be an issue.

Where all does the thick B+ wire from the alternator run to? There is a really thick wire in front of the firewall with three wires coming off of one end; I believe the thick wire coming off of it leads to the alternator. However, the thick wire burned in two right next to where the wire splits into three wires. She called it a "stator" wire, but no one I've talked to knows what that is.

I'm also wondering what the easiest way would be to reach the alternator, and what all of the terminals are. I have a Haynes manual, but as usual its fairly vague and the alternator diagram listed isn't the Nindispenso.

It's Nippondenso, aka Denso. There are 2 part numbers; 5234026 for 34/75 amps and 5234199 for 50/120 amps. Both are 2 groove pulleys.

From the '90 service manual:

1. Remove the negative battery cable
2. Remove alternator drive belt.
3. Remove the alternator mounting nut (top) and bolt (bottom) and separate the alternator from the mounting plate.
4. Remove the B+ terminal nut, 2 field terminal nuts, ground and harness hold down nuts. Remove wire connectors.
5. Remove the alternator from the vehicle.
6. Installation is reverse of removal.

B+ = Battery plus


My scanner's broken at the moment, so I can't scan the page for you...

I believe the reason for the short was the harness hold-down wasn't bolted down, and this caused a wire to go somewhere that it shouldn't. Just to make sure, is that by chance attached to the B+ wire? There's like a black box thing on the wire a few inches away from where it bolts to the alternator, and what looks like a terminal attached to it. This wasn't bolted to anything, and I'm sure that terminal serves a purpose. It could either be the mounting hole referenced in the instructions, or perhaps something else?

Yeah, the wire harness hold down is on the left if you're looking at the back. The bolt at the end of the wire, on the right, is the ground (-) terminal. And the B+ wire loops just below that to go to the B+ terminal.

I'll see if my all-in-one wants to scan today (sometimes it won't) and try to get a diagram up for you.

Got it..amazingly.

Attachment 108758

That should help out a lot. Thanks!

Alright, here's another question.

I have access to an alternator for $20 from around the same year. Its the other alternator, not the Nippondenso. It does have the correct double pulley. Can I swap this in, or do I have to go with another Nippondenso identical to what came out?

Are the connection points the same? If it looks identical then it should fit.

If you mean do they have the same connections, I believe they do.

If it has the same connections, you should be good.