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Discussion Starter #1
I am having to charge my battery on the charger every couple days. I have a brand new alternator, battery (replaced these twice to be sure), new 2 gauge battery cables (all 3 of them), new solenoid, new starter, new alternator wiring harness, etc. And still... it won't keep the battery charged. I keep getting stuck about halfway to or from work losing power and having to pull off the road because the battery has died.
I'm fairly new to ford charging systems... is there something I am missing here? All grounds are in tact, battery, alternator and starter are new and tested good to be sure. WTF am I missing?

HELP!! ASAP! thanks
 

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Geez, something is taxing the crap out of your battery, huh? Not many things could drain it dead like that, especially if it's going down while you're driving?!?!. I know you said you have a new alternator, is the belt tight? Sounds like the alternator isn't charging the battery at all...
 

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Discussion Starter #4
ok, first off, I do own a multimeter. I checked output of the alternator and got nearly 15 volts but when I attach the wire to the solenoid, it drops to around 12 (if that). the belt is tight and new.

Thanks for talking down to me steve, but when you having a charging system problem, and there's only a few charging system parts, it's usually a no brainer as to what the problem is. I work at Azone and at a garage, so I have a multitude of testing equipment at my disposal as well as replacement parts. However, I can't find anything wrong, so I turn to those that have similar vehicles with more experience and ask for help.
 

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The Anti Yam!
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Timberwolfz28 said:
I checked output of the alternator and got nearly 15 volts but when I attach the wire to the solenoid, it drops to around 12 (if that)..
Then you have a short to ground past the end of that wire. It's does not sound like the alternator to me.

Do you have any extra stuff wired up to the battery or solinoid?
(Amps, lights, etc)

Any part that comes from autozone is suspect right out of the box.

Timberwolfz28 said:
I work at Azone
I wouldn't tell anybody.
 

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There is a number of things it could be including a short but test the voltage regulator and the alternator and the battery. Does your gauge show it charging when you are driving? Do you have an electric cooling fan? I'm with Gack, it doens't sound like the alternator but more like the regulator.
 

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you said 15 volts then drops to 12 connecting the solinoid? then you got a draw at the solinoid. remove aa wires fron the solinoid and check voltage again. your power to the cab connects on the battery side of the relay. i bet you got a short from a bad wire or switch inside the bronco. you might need to make a couple jumper test leads to get power to the inside without connecting them to the starter relay........mike
 

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The Anti Yam!
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Go to search.

Put in Battery Draw into the key word search feild.

Switch the search function to Search thread titles only.

If you do that you will find this thread. (the first one)
http://fullsizebronco.com/forum/showthread.php?t=58167&highlight=battery+drain

Post # 10 tels you how to measure the draw from the battery.

There are also 6 other threads that come up and can show you how to find your drain. But to get to those, you will have to do your own search
 

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Ex Navy Nuke
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Gacknar said:
Then you have a short to ground past the end of that wire. It's does not sound like the alternator to me.
I totally agree. You need to troubleshoot for a short/drain on your battery. Have you done any other work on the Bronco recently that may have caused an eletrical short? Any work even if you don't think it could cause a short is suspect, double check anything you may have done? My ECM relay went bad recently and killed a 9 month old battery. I do mean killed, after sitting for 5 or 6 hours it didn't have enough juice to crank the engine over.
 

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Discussion Starter #10
I tested everything before it went on the truck and tested the stuff that came off the truck. Everything tested good. But since I get a deal on parts, and it's an older truck, I replaced the parts anyway.

Forgive me if I am wrong here, but with it being an 89, the voltage reg is internal to the alternator, correct? I'm not well versed in older ford charging systems, but I thought it was internal from 87 and up.
 

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Discussion Starter #11
just remembered some more info...if it helps. When the truck is running but the battery isn't dead enough to cause it to stumble, I can unhook the battery cable and it runs fine. If it's already faltering from the battery being so low, when I unhook the cable it will stumble worse while surging a bit, then it will stall. Sometimes I can give it a few revs and it will light back up and not stall, but most times it won't.

What wires should be hooked to the battery side of the relay? I have the two yellows, the battery cable itself, and a couple others that I haven't tracked to see where they went, but I not knowing what they were, I haven't unhooked them to see if it works better because I didn't know if the truck would even run without them. Like I said, I'm fairly new to fords...
 

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It won't run w/o them but you still need to check for a draw on the battery. Disconnect the neg batt cable and hook your meter up between the neg post and the cable. Make sure it's set up for amps. See how many amps are flowing through the system then disconnect the little yellow wires and whatever other wires you have on the battery side of the relay one at a time. If you have a draw on the battery you should see at least a couple amps on the meter. When you disconnect the wire that powers the load that is causing the problem the amp draw should go away. Then it's just a matter of getting out your wiring diagrams and figuring it out.
 

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When you replaced the alternator,did you replace the plug that plugs into the alternator(the one with the 2 large wires and 1 small wire)?Ford and the alternator rebuilders recommend replacing this plug due to poor connections causing high resistance and low output.This could account for the output being 15 volts with the alternator charge wire disconnected,then drops to 12 volts when hooked up.
 

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Discussion Starter #14
bronco1 said:
When you replaced the alternator,did you replace the plug that plugs into the alternator(the one with the 2 large wires and 1 small wire)?Ford and the alternator rebuilders recommend replacing this plug due to poor connections causing high resistance and low output.This could account for the output being 15 volts with the alternator charge wire disconnected,then drops to 12 volts when hooked up.
I replaced the big rectangular plug...tot he rectifier I believe. it was in poor shape. I thought sure that was the problem, but it didn't help. So I swapped the complete alternator harness with the one from my f150 just to double check (it charges fine) and no go.

One thing I did want to mention... I can let the thing sit for days and the battery won't lose charge. Whatever it is, only happens while running...
 
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