dewclaw

An earlier post said that my alternator died . I could see that the field winding were discolored and burned looking. I figured , ok , 195k mi. , its was time for one to wear out .
Well I put a new one on. I noticed that the voltage output was only about 11 volts. the old one ran at about 14 before it took a dump. I ran it all over town today and late in the day I got the same thing as before "check gauges" light came on and it wouldnt start after I shut it off.

The alternator was really hot and I could see that the field windings were getting discolored.
I checked the wiring that is connected to the alt and none were hot .
The only elect. mod. I have done was adding some backup lights , protected by a fuse. That wire was not hot . I checked inside both fuse boxes and nothing was hot.

Would this happen if the batteries were bad ?

Can anyone help me / What should I check , how do I do a process of elimination ?!!!

Im totally stumped.

Please help.
Thanks,
Brett

Fueling around

Basic questions here.
Did you get the batteries load tested and charged before you installed the new alternator?
Alternators are meant to only recharge slightly discharged battery(s). A flat battery must be done by a charger.
I fought a problem this winter that turned out to be a bad battery. They both passed a basic voltage & load test, but I finally took it back to Sears and they put it on the battery analyzer. One failed bad and the other tested as new.

Checked all battery cables including ground points?
Poor connections are a sure way to kill the electrical system.
A poor ground at the PCM (which drives the alternator) is another check point

12valve@heart

Another basic question that comes from having worked in the parts business. Did you have the new alternator bench tested before you put it on? Regardless, you may want to pull it off and have it tested now to make sure that it's not part of the problem. Yes, new/reman parts can be bad when you get them.

Haulin_in_Dixie

Yes it does sound like you may have a shorted battery, better get them checked.

dewclaw

Yep, I will have the batteries tested tomorrow. If needed I will have the alternator bench tested also.
I charged them all night before installing the alternator . (they are on the charger again right now)
Also before starting the truck I cleaned and coated the terminals/connectors and coated them with anti corrosion goop. The batteries are right at 3 years old.
Hope I didnt totally cook the new alternator.

Thanks for the input everyone !!

I'll let ya know how it goes.

~Brett

dewclaw

Bad batts, alt. is still working but may have took some life out of it getting it hot . Two new die hards $183.00 ouch.
Thanks for the advice all !

Fueling around

The alternator is actually a very durable unit outside of the slip ring.

Which batteries did you get for that much loot?

BTW, if anyone needs alternator parts I found a good source for reasonable prices.

Northwest Power Systems in Thief River Falls, MN. I got a new rectifier bridge and brushes for under $50 with shipping & tax. I ordered them at 5:00 PM and had them the next day (only 45 miles away).

-John

Haulin_in_Dixie

Alternators are simple but there is always that mavrick. I have one downstairs that is less than a year old. The windings have continuity, the diodes all check good, the brushes are great. It just won't charge. I even changed the diode bridge so there is something in the windings wrong. Must have an open that will conduct with an ohm meter.

4x4dually

If you find yourself buying new batteries, splurg and get the new spiral cells from NAPA. I have had them for 5 years now and they are well worth the money (at $124 each at the time). I like them so much, I trade them from my old truck to my new truck before I traded it in. They spin that big honking CTD much faster during cold starts.

.02

Fueling around

My father made a tester with a light bulb in series with 110v line voltage for those annoying units.