need help tracking a short

[rockyrunner99]

I had a thread going as alternator, that is what the problem initially seemed to be. I have a short traced to the large wire connector on the firewall next the computer. I can not figure out where to go from here. It is kinda a odd short too. It seems to be a major draw, yet the battery has not died yet. The alternator will only charge at higher rpms. With cold weather coming later today, I really need to get this figured out. I have ruled out many things. Almost any connector I can get to I have unhooked. I have ruled out the ignition switch, headlight switch, most all the engine connectors. I have also pulled every single fuse one by one and, and the short did not go away. That is what has me stumped. From the wiring diagrams, I can not see what is powered through the PDC that is not fused.

If this short is drawing 10-15 amps, will this severely shorten the life of the alternator. I have been driving it this way for a few days, and the battery seems to be getting a enough of a charge to maintain. If I keep driving it though will I burn up the alternator within a week or so?

 

[rockyrunner99]

I am getting closer. My process of removing one fuse a ta time does not help when there are multiple circuits with a short. I removed them all and replaced them one by one. There are 4 circuits on the inside fuse block with a short. I am trying to get to the back of the fuse block to check that, I find it hard to believe that 4 separate circuits would get a short at the same time! I think something has fallen in the back of the fuse block, but I can't seem to get in behind it to look.

 

[Alvin in AZ]

Cool updates, thanks.

Just keep at it, you'll get it, it can't get away from you now.

Alvin in AZ

 

[rockyrunner99]

I am back to thinking it is the alternator. I think the draw I see on the test light is the radio and remote keyless entry, and speedometer memory that are drawing a little current all the time. The volt gauge on the truck made me think it is a large draw, yet the battery is never week after sitting all weekend. I think and other people have suggested a diode out in the alternator or a broken winding. Either way, I am looking for a used one, to put in so I can rebuild this one. I can still drive the truck fine most the time, the only issue is when I need lights, and heat.

 

[Alvin in AZ]

I don't have any idea how reliable the test really-is but the auto parts
places will test alternators for free. BTDT and they were glad to do it,
had 4 of them to test all at once even.

Told the guys up front what my plan was, to replace the bearings and
brushes in 'em myself if they tested good, which all of them did.

-------------------

Hmmm... just remembered... one was a brand-new-looking DuraLast.

I mean it looked like it'd just came out of the box, got it out of a wreck.
He offered to give me a replacement on the spot because the bearings
were noisy as anything! Out of all the old used-up looking alternators I
had, that "new" DuraLast was by-far the loudest. LOL I declined the
offer. Told 'em the next one might be worse and he agreed. LOL All
it needed was a new front bearing which is a 6203 bearing.

Worked with a guy in the Sufferin' Pacific's System Signal Shop in
Sacramento, that had worked in a auto parts rebuilding plant...

"first thing we did was to clean all the stuff that came in, next was to
test all of it and the ones that tested good went straight into a box
and shipped right back out! " -Bruce Turner

We all thought it was funny as anything.
Knowledge -is- power if you got it and a real-***** if you ain't.

Alvin in "Arizona"
ps- How's it hangin' Bruce?

 

[rockyrunner99]

Well I finally got this all figured out this weekend. It was easy, took the alternator to NAPA, the tested it and could tell the diodes were good, so it looked like a bad winding. So it was a new alternator for me.

 

[rockyrunner99]

Well, I might have more problems now. Earlier this week, I started getting a burning electrical smell coming from the engine. The only thing warm under the engine electrical was the alternator. I think the alternator is overcharging, it is brand new. Since is it 5 degrees out right now and I do not have a garage to work on it in. I will have to wait a while. What might be some possible causes for this. Dead cell in battery, Bad ground, or bad connections at the alternator. Are the first things I can think of to check. I am afraid it will be the bad connection at the alt. I and removed and reinstalled the alternator a couple times, and the large connector plug was not fitting all that tight anymore. I used dielectric grease on it and I pulled to make sure it would not come off though. Thanks for any other input before I brave the cold to work on it.