Alternator problems...

[LPCL_Geesaman]

I recently got the M1009. the blazer worked well at first than we hit all kinds of electrical problems. you all know it has the 24v/12v system. first off the alternator's were not charging. so we started looking at it and lost all the power. after about two weeks we have it starting now. The only down side is we had to unhook the passenger side alternator because it was sparking and smoking. I have no idea what to even look for. Any help at all would be Awesome.

 

[ralbelt]

I think the electrical guru's are going to need to know what has changed since it ran well and now sparks. Did you change the alternators or changeout any electrical connections. Also check out the tm's for more info.

 

[Warthog]

Welcome to SteelSoldiers.

Your first stop needs to be the CUCV Wiki that is at the top of the CUCV Forum. All of the techmanuals are listed there. Read, read and read some more.

Then visit the CUCV FAQ sticky that is under the Wiki. It has alot of info listed.

Also get to be friends with the advanced search feature. Almost every issue you have and will have has been asked and answered many times.
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Now to your issue.

The CUCV electrical system is very simple once you get a grasp on it and learn to read the electrical diagrams.

If you changed the passenger alt and didn't reinstall an "isolated ground" alt then yes it will spark as you have created a direct short for the batteries.

What experiance do you have with this electrical system? Have you download and read the manuals? Have you searched for alternator solutions?

We will need more info as to what was working, what was changed, etc.

 

[LPCL_Geesaman]

Well the capacitor between the negative and positive lines in the terminal block was broken. we couldn't find another 100v so we put in a 50v. we also found that the battery closest to the grill didn't have the ground wire on it so we put that back on. we also replaced some fuses but other than that we didn't change anything. when we replaced some fusses it fired up but the alternator is still sparking. it starts slow but she still fires up. once we get the alternators fixed she'll be a beaut again.

 

[1stSarge]

I am posting here so you can note the links in my signature. I can only add what I have learned in the last couple of months. You are already talking to probably one of the best electrical “gurus” on the CUCV. (Warthog) Many of the links below were written by him.

As you study the wiring diagrams, you will come to see how useful some of these links are. For example, a single burned out light bulb will keep your alternator from charging.

Like he said, learn to make the search function your new best friend, you will be reading for days.

Heres a quick one to get you started:
Steel Soldiers::Military Vehicles Supersite - Search Results

Welcome to the site LPCL, we are all just a shout away.

 

[Dabba]

Id have that alt tested, and then check the diagrams.

 

[Warthog]

Well the capacitor between the negative and positive lines in the terminal block was broken. we couldn't find another 100v so we put in a 50v. we also found that the battery closest to the grill didn't have the ground wire on it so we put that back on. we also replaced some fuses but other than that we didn't change anything. when we replaced some fusses it fired up but the alternator is still sparking. it starts slow but she still fires up. once we get the alternators fixed she'll be a beaut again.

The suppressor between the Neg and Pos terminal block is used for noise reduction for the 24v Military Radio Systems. It is not needed for everyday use. I have seen many that have shorted out and where removed.

The front battery is tied to the driver side alternator and supplies the 12v that the majority of the CUCV electrical systems use.

The rear battery is tied together with the front in series to supply 24v to the starter, glow plug system and military radios. It is charged by the passenger alternator.

The missing ground wire for the front battery. Was it the small wire or the 2 gauge heavy wire?

The fuse box is an issue with almost everyones truck. With the trucks being 25+ years old and the hard/harse life they have had, they are dirty and corroded. When you have time, disconnect you batteries, remove the fuses and clean the fuse box with some electrical contact cleaner and some sand paper if needed.

With the description of your issues, I would say that the previous owner had issues and changed some of the electrical wiring. So the question is do you want a stock wired truck or a modified wired truck?

If you want a stock truck, you will need to download the tech manuals, read the first few pages of the troubleshooting section that explains how to read the wiring diagrams, print off the wiring diagrams from the appendix and start checking to make sure the previous owner didn't modify the system. Without knowing that the system is wired correctly, it will be difficult to begin troubleshooting.

That being said it isn't that hard, just time consuming.

Do you remember which fuses you replaced? It is possible that when you replaced a fuse, you energised a "modified" circuit.

 

[mistaken1]

How long did it run after you got it?

Is it possible someone put a standard grounded case alternator on the passenger side before you bought the truck?

 

[wallew]

The fuse box is an issue with almost everyones truck. With the trucks being 25+ years old and the hard/harse life they have had, they are dirty and corroded. When you have time, disconnect you batteries, remove the fuses and clean the fuse box with some electrical contact cleaner and some sand paper if needed.

OOH, OOOH, I gotta 'cheat' for the sand paper part.


Use an Emery Board. WORKS GREAT. Stays stiff for a while ( NO JOKES).

Just don't tell your WIFE why you took it OR what you will be using it for. I also have a skin scrubber that is similar in size to an emery board (looks like pumice to me) to clean larger electrical pieces. BOTH WORK GREAT and I've been doing this for years and years.

 

[Warthog]

....Just don't tell your WIFE why you took it OR what you will be using it for.

Been there and done that.....she keeps them under lock and key now.....LOL

I keep forgeting to buy me some at the store.