Alternator Dying-Updated 1/1/11

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Could it be that you have two issues? No one seems to be arguing that the auto parts store cannot diagnose a bad diode, I have no doubt that they can. The question would be, is that the problem with the battery going down.



IMHO, if the Alt is testing bad, replace it. THEN move on if the discharging issue persists.







(I may be a "Shade Tree" mechanic, but there have been a LOT of cars & trucks under my tree, and very few of them for the same problem again) :grin:
 
OK, well I've already bought a new alternator. Bought it Monday night. I'm planning to remove the old one on Saturday morning. Maybe I'll run it to the store and have 'em test it prior to installing the new one. If it's bad, I can install the new one, then drive to the store and have the battery tested again after removing both cables. That way, it'll be totally isolated.
 
All you need is a multimeter that has an amp setting on it. Disconnect the negative battery cable, take one of the mutlimeter leads and clip it to the negative battery terminal and take the other lead and clip it to the negative battery cable...now you are seeing how much amperage the system is drawing. When you do this make sure that all the doors are closed, the keys are out of the ignition and that the underhood light if you have one is unplugged. If you watch the meter when you first connect teh clips you will probably have about a 1.5 amp draw that should drop rather quickly, now go grab a beer and come back in an hour and see what teh meter reads, if it's anything over .050 amps you have an issue. At this point if you suspect the alternator then completely disconnect the alternator and start the process over.
 
Last edited by a moderator:
l1tech,



If you watch the meter when you first connect teh clips you will probably have about a 1.5 amp draw that should drop rather quickly, now go grab a beer and come back in an hour and see what teh meter reads
Click to expand...



Is that a quote from the offical Ford Service Manual, and does it include getting a beer or were you just improvising?? :haveabeer: :grin:



...Rich
 
TT,



Did you try my suggestion?



It will isolate if you have an alternator or a vehicle issue.



Simple and effective to at least isolate the direct and money you need to spend..
 
Coastiejoe,



I did indeed . See my posts in this thread from 11/16/2010 18:59 CT and 11/17/2010 06:54 CT .
 
Well, I swapped it out this morning with a new one. Not a difficult job at all. Just a little time-consuming removing other stuff (TB cover, intake, etc.) to get to it.



I'm going to take the old one to Advance Auto on Monday and have them bench-test it. I also won't be driving the Trac until Monday morning, so if the battery's dead on Monday morning, I'll know it wasn't the alternator.
 
Well, prior to this morning, the last time I drove the Trac was Saturday morning to move her out of the garage after the alternator swap. Went out to go to work this morning, and the frakkin' battery was dead again!:angry:



I'm stopping by Advance Auto tonight after work to have the original alternator bench-tested and also have them load-test the battery after I completely disconnect/isolate it from the vehicle.



Maybe the one-year old Optima battery is bad after all. We'll see...
 
Sorry but I had a feeling this was going to happen



Bench testing the alternator is going to be futile, they are going to give you the same results as they did before, the results wern't right then and I wouldn't expect them to be right this time. A simple load test with an actual battery load tester...not the the conductance tester will tell you in a heartbeat if it's the battery or not.



IDK about you but if it were me I would be returning that alternator
 
Bench testing the alternator is going to be futile, they are going to give you the same results as they did before, the results wern't right then and I wouldn't expect them to be right this time.
Click to expand...



Why not? Wouldn't the results be more conclusive in a bench test, with the alternator alone, and isolated from the rest of the vehicle?



After work, I had the original alternator bench-tested at Advance-it was indeed bad. We then went out and load-tested the battery after I disconnected both terminals. It tested good, just not fully charged because I'd never put it on a charger after it was drained before; I'd just jumped it and went on my merry way. The Trac's now in the garage with the charger on it. When I first connected the charger, it showed the battery at about 50%. I'll let it sit overnight on the charger and then see how the battery holds up later this week.
 
There really isn't any way that you can test an alternator on the bench that you can't test in a vehicle, with that being said it is always be better to test anything, be it an alternator or a soup spoon, with it being used in it's environment then to take it out of it's environment and then test it. Just out of curiousity what did the parts store say was wrong with the alternator this time when they bench tested it? Please tell me that they used an actual battery load tester and not a conductance tester that doesn't actually load the battery when they tested it. I'd bet you a million dollars that when you get the issue resolved whether it be a bad battery or a parasitic draw that you could reinstall the original alternator and if would function like it's supposed to but here is the kicker out of all of this...a cheap $20 (if that) multimeter that had a low amps setting on it could have told you what the problem was in an hours time...this is what 7 days now and all you have is a lighter wallet some dirty fingernails and a truck that still won't start after a day or 2.....just trying to be helpful but I'm guessing it sounds more condenscending than anything.
 
I just had the same symptoms start. I also did some routine maintenance today hoping it would help. I just replaced the belt, and the idler and tensioner pulley's, as I have 104,000 on my 05. I took it in today, and they tested the 11 month old battery and alternator (original). Said both are fine but I have a 3.6 amp discharge when the vehicle is off. Suggested taking it to an electrical service center........ this sucks, it sould like I have an electrical issue, I was hoping it was the battery or even the alternator... any ideas? I am reading the above posts and am not sure how to determine what the problem is, I am buying the draw to the system for up to 45 minutes, so what is my next step, I dont have the luxery of another vehicle to take the alternator off and have it bench tested.



Thanks
 
I ended up getting an AutoZone Gold Battery about three weeks ago. Installed it, and then let the Trac sit over the following weekend without driving her. Come Monday morning, she fired right up.



She then sat in my driveway for nine days (in very cold temps) while we vacationed in San Diego. Upon our return home on 29 December, I went to check things out. She turned right over and fired up without a hitch! So after a new alternator and battery, I'm declaring this problem solved!:banana:
 

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