i've noticed my battery gauge not being where it usually stays within the last week and a half or so. TJ is gonna laugh at me some more but it usually reads at the "m" or the "a". now its barely even touching the "n". today it finally just clicked when i tried to crank it. mind you i drove it to work then 10 minutes later went to start it and that's when it was done for. started fine first thing this morning. i pulled out the battery tester and as my batteries are supposed to be 675 cca, i tested the passenger side batt. first and i read 12.4v and 283 cca. then i tried the drivers side batt. and it read 12.5v and 1311 cca!!!!
anyways, i switched the battery sides (put the drivers side one on the pass side and the pass side on the drivers side.). after that she cranked right up but still reads low on the guage. i did clean up the terminals nicely, but i know something is not right.. at night time the lights have been dim at idle then once i start moving they get brighter, but tonight they just stayed dim.. i'm thinkin' alternator, but maybe the crossover batter lead that connects the 2 batteries???? i'm not sure what to think about this so any help is greatly appreciated!!! thanks guys!!

 

Sounds like the alternator to me. Did you double-check the plug on the alternator? I hear that can work itself loose from people laying across the top when working on the engine.

Did you try to charge the batteries? Are the batteries holding a charge? I'd remove the alternator and have it bench-tested. NAPA, AutoZone, the usual parts places should be able to do that.

 

Travis, it's probably the voltage regulator on the back of the alt. I would try that first.

 

put the system on a load test today and it was puttin' out negetive voltage. so it shows that the alternator is pulling voltage from the batteries??? where is the voltage regulator at on this thing? i have never heard of it or seen it so i don't know what i'm looking for. thanks guys

 

Not sure that negative voltage is possible. Probably had the leads hooked up wrong.

 

ya, just like if you put a volt-o-meter on the battery backwards, it reads neg. i would just take the positive of whatever number you got.

 

i had the leads on correctly. i didn't think it was right, but i got my auto tech teacher to look at it and he said everything was on right. i guess my alternator is actually drawing off my batteries or something like that, but i have never seen that either. so even if i take the positive of what it gave me then that's about 4v that it would be putting out and that means my alternator is still screwed. everytime we loaded it up with the truck running the battery gauge dropped to nothing, the tach dropped to nothing, and the abs light and stuff came on. it was really weird, but i'm gonna charge up my batteries and run it tomorrow and get my alternator on there tomorrow during 3rd period at school hopefully. thanks again guys

 

That is definitely your alternator maybe burnt diodes inside or bad bearings, I just had mine rebuilt for $50 and it is good as new

Good Luck

 

hmmmmm, you got my attention now!!! is there any advantage/difference to having one rebuilt or getting a remaned part from the auto parts store? is one better than the other?

 

I would say that is a decision for you to make,from experience rebuild is just as good as buying a re-man but nothing com pairs to new LOL

I have never had a problem with the rebuilds the guy that does it for me has been in business for 25 years and is a small shop

GOOD LUCK

 

Negative polarity can happen and that is certainly diodes in the alternator. Not good to run the battery that way.

 

the new alternator i priced was 700 bucks!!! LoL. i'm gonna get a reman tomorrow and stick that mother on during school. thanks guys for all the help!!!

 

you can get a 215 amp ambulance alt for a little more than half of that!

 

then why was the stock replacement one so much?!?! if i was going with a brand new one i would go for that, but right now i'm not in much of a spot to be throwing to much cash at this thing and with dyno right aroung the corner i'm not too sure that this truck will make it on the rollers or not the way things are going lately with it. thanks tim for telling me that, next time this thing craps out on me i will definitely be gettin' me a 215 amp since i run a big amp for my stereo.

 

From where? Are modifications to the stock mounting brackets needed or does it come with new mounting hardware?

Part number would be helpful if you have it.

What is the stock alternator rating?