OK 1st. genners her's what's happening.I drove truck sunday w/lights,wipers, and heat going ( big rain storm ). I got up mon. for work and starter just clicked. So i jumped it went to work and amp guage showed no activety. I came home and put charger on it went to work next day started fine but guage didn't move at first then jumped to normal 14 v's after about 10 min. then settled to about 12 v's mark and is still there. Tonight i had it checked with analyzer at Auto Zone hooked to battery and it read 12.47 v's dropped a little when loaded then went to 12.47 v's.Auto Zone guy suggested putting on bench for test but i wanted to run it by ya'll first. Any suggestions?? Right now i'm OK if i charge overnight but need to get it fixed soon.

 

What year truck?

 

This has happened to me. Sometimes it would charge and sometimes it wouldnt. New voltage regulator fixed me right up... hope its the same case for you.
Like Wanna said, what year is your truck? We can help more

 

Sorry I Forgot To Tell You It's An 85 D- 350 Crew With A 91.5 12. I Did A Conversion

 

Also Where Is The Voltage Regulator ? Is It In Alternator Or External Mounted. I Have A Small Box In Fire Wall About Midway But It Doesn't Look Like Regulator

 

It's an external VR, and it should be in the middle of the firewall above the engine.

 

Is The Vr Something I Need To Get From Dodge Or Will Auto Parts Store Have It. Is There A Way To Test Vr Before Replacing? I Guess The Box I Was Looking At Was The Vr Then. It Would Be Much Easier To Replace It Than To Pull Alt. And Take To Have Bench Tested!!

 

You can get them at pretty much any parts store. Price range from $20-$40. Yes, its much easier to spend 2 minutes changing this then pulling alternator Good luck!
Dan

 

Hey guys thanks for the help i will give the vr a shot and see what happens . I will keep you posted.

 

I had the same problem and I replaced the v box on the fire wall. Tha 1991 has a grouding problem so I ran a ground strap to the block and it fixed the problem. Hope this info helps.

Charliex25

 

JUST AN UPDATE ON THE ALTERNATOR SITUATION. I RECONSIDERED THE PULLING OF THE ALT. AND DID IT TOOK IT TO LOCAL PARTS PLACE AND HAD IT CHECKED. MACHINE SAID IT WAS BAD SO I GOT Boo! Boo! FACED AND THE GUY DECIDED TO TRY THE SAME ALT. FROM HIS SHELF AND IT FAILED ALSO. THREE MORE ALT. FAILED ALSO long story short HIS MACHINE WAS BROKE. (in future remember this guys!! ask to check alt. from shelf to verify machine is working!!! ) ANY WAY I BOUGHT VOLT. REG GOT HOME PUT EVERY THING BACK TOGETHER AND VOILA!! STILL NO CHARGING. IT WAS MAKING A CLICKING NOISE WHEN I TURNED ON LIGHTS AND GAUAGE WOULD MOVE UP AND THEN DOWN WHEN YOU HEARD CLICK. THE GAUAGE SHOWS ABOUT 12 V SAME AS I DESCRIBED IN PREVIOUS POST. DOES THIS TRUCK HAVE THE SENSOR TO ACTIVATE CHARGE PHASE OF ALT?.I AM RUNNING OUT OF IDEAS.

 

How many miles does alternator have on it? If its pushing 150,000 miles or more it could be a brush problem. I run in to that a lot where I work. I have seen the brushes wear our a lot quicker than that,if it's being worked harder,by extra lights,or a big stereo system.

 

Check the grounding of the VR. I whacked mine when it started getting "funny" (just like with the old mechanical VR's) and it is behaving again. I intend to put a ground strap on it as others have mentioned.

 

If your air or cruise doesn't work it's the crank positioning sensor, not the VR.