Alternators installed backwards

[bchesley]

I purchased my M1009 about 6 weeks ago and have been slowly going through it and fixing little odds and ends. All the while studying this site and the wiring diagrams. I realized this weekend when I started testing the charging system that my alternators are backwards. What I mean is the Isolated ground alternator has been installed on the Drivers side, and the non isolated ground on the passenger side. The wiring has been modified too. From what I can tell I have all the correct wires going to the righrt locations, I am just not sure that it will work this way. I have attached photos of the install. Is it worth my time to undo this?

 

[Warthog]

Awwww... the joys of fixing other peoples "repairs".

The nice part about having the wiring stock, is that someone across the country can help diagnose a problem. With modified wiring, it is a crapshoot.

If you don't atleast figure out what yopu have now, you will be on your own when am issue arrises.

I would say you need to figure out what was modified and then if you are up to it, return it to stock.

 

[bchesley]

I was on the fence as to what to do, mostly because I am already knee deep in other projects on it, but the more I think about it I will likely put it back to stock. None of the Gen lights on the dash work like they are supposed too and I am not sure that the Gen 2 is even charging. I had 14.5 volts on the front battery and 12.7 on the back. But because of the switch up of the atlernators I could not figure out what was going on. I guess I will add that to my list of to do's.

 

[boondock]

I agree with the suggestion of returning the wiring to stock as this eliminates areas of concern when you are trying to troubleshoot future possible electrical issues.

 

[AceHigh]

It looks like your glowplug resistor has already been bypassed so you are already part of the way.

 

[doghead]

Check and confirm your GP relay is isolated.

 

[bchesley]

The glow plug system is my doing, and I used the part numbers found on this site to convert it to 12 volt. I also added some AC60G's too. No more ether to start it with. And thanks to you Doghead this weekend I did your mod. I have been checking off the list of things to do and checking the charging system was next. looks like I will be tracing lots of wires this coming weekend. I did also order the CUCV electric relay kit so that might help me too. I am finding out that CUCV owners are alot like IH scout owners in that they can really screw one up trying to rig stuff. The previous owner says that he got it this way so it could have left the base like this.

 

[SPECIALTYLC]

In stock form, both alternators have isolated grounds and are interchangable.

 

[bchesley]

Dang, then I might have a problem. Only one of my alternators has the second post/isolated ground. I will take some better pictures and post tonight. Thanks.

 

[Jersey4x4]

Yep, Both alternators should be the same 27SI isolated ground units

 

[doghead]

Let me clarify the facts.

In original stock form, they had 2 identical alternators installed.

One of them gets grounded directly to the engine with a short black wire.

So, theoretically(and factually) you can use a standard(non-mv) case grounded alternator, on that side. This is the Drivers side alt, for the front battery(in stock correct form).

 

[bchesley]

Well, as my luck would have it, its a non isolated ground alternator. I am going to be really anal about this and add the right alternator. I am also going to redo the wires back to stock. I have already found where the wires were cut at the end of the wire loom near the block. I have searched the site and found Napa carries the right one that is a Wilson rebuild. I dont mind buying one already rebuilt, but the comments said to check them to make sure its an insulated ground. If I go that route how do you check it? Lastly, anyone have a stash of good alternators that would sell me one?

 

[bchesley]

Just a little update. This weekend I dove in head first and fixed the previous owners debacle.

First, what I had to begin with was a non insulated grould alternator on the passenger side and an insulated ground on the drivers. The previous owner instead of installing the non insulated alternator on the drivers side decided that rewiring the truck would way more fun. All of the large power wired had been cut at the end of the wire loom. They then decided to flip all of the wires outside the loom to keep the alternators in a series but completely backwards. It took a lot of thought on how to do this when all it would have had to happen is a 5 minute swap of the alternators.

I now have a factory schematic with the right wires to the right alternator. All I need now is to find a new or rebuilt isolated ground alternator without breaking the bank. Thanks for the help with all the other threads on alternators.

 

[doghead]

It's amazing what people will do, especially when they simply do not understand the system.

Glad you have it figured out now!