I have an 89 ford Bronco 5.0. I have replaced the battery and the alternator. The battery runs dead sitting with the ignition off. I have disconnected all of the wires going to the cab and the rear end. I tried disconnecting a wire after each charge on the battery until I limited to a set of wires going to the alternator. There is a round black box next to the battery that the pos and neg cable of the battery connect to. The box has a third smaller connection that a small wire connects to. I think this box is a starter relay. Anyway the ground for the battery goes to one side and the positive to the other. On the positive side there are three yellow wires and a green wire (the green wire is the one going to the alternator). With all the wires removed except the green the battery still dies. when I disconnect the green wire the battery stays charged. The wire fuzes into three wires all go to the alternator. the wires look ok. I have hooked a meter to the neg side of the battery and to the green wire while the pos side of the battery was disconnected and I still get tone indicating a ground exists. I believe this is why the battery is dying. Can anyone tell me what would be causing this and how to resolve the problem?

Thank You,
Chuck

 

Replace the regulator. And oh, by the way, that is not the negative wire on the other side of the starter relay. That is the wire going to the starter. The negative of the battery should be bolted to the engine block somewhere.

 

Thank You,
I will try that.

Chuck

 

Thank You. The regulator is in the alternator. I replaced it as well as the wires going to it. You are right the other wire on the starter relay goes to the starte, I don't know what I was thinking. The battery draining problem however still exists. Can you tell me what side of the starter relay the wire from the Alternator goes to? I think it goes to the battery side however I am havib=ng a hard time finding a good diagram.

Thanks,
Chuck

 

Whoops, sorry about that. All my diagrams for the chassis wiring only go to 86. I didn't realize Ford went to an internal regulator. Nothing should be on the starter side of the starter relay, since it will be dead unless you are cranking the motor. You did a good job of narrowing down the certain wires causing the drain, and if they go to the alternator, could it be a bad new alternator? I would say yes if you replaced the alternator for another problem, and this is a new problem that developed. Of course if you replaced the alternator for the draining problem, you wouldn't think two alt would have the same problem.

 

Yes I did replace the original alt for the same reason but the new alt did test with weak output so I have exchanged it. I will try it to see if the problem is resolved. Thanks for the information on the wiring.

Chuck

 

 

Take a Test light and Attach the Clip end to the Positive post of the Battery,then touch the Probe end to Ground of vehicle > Does the Bulb light up ? If so there is a Short somewhere.
Now the fun starts.
Disconnect one fuse at a time and try the test light until it doesn't light up.
That's the circuit that has a short in it.

Dennis

 

mil1ion, I think you know what you were trying to explain, but I think it came out wrong. You have to take the battery cable OFF the battery post, and hook the test light between the battery post and the battery cable.

 

I've got the exact same problem with my truck... there is something that's drawing current when its shut off. I will try the same method of testing to attempt to isolate the problem. Its kinda a pain to have to pop the hood everytime you want to go somewhere!

James Kern
1970 F250 4x4

 

[font size="1" color="#FF0000"]LAST EDITED ON 22-Oct-01 AT 00:09 AM (EST)[/font][p]https://www.ford-trucks.com/dcforum/User_files/mil1ion/3bd39b4a0996928b.gif
I had forgotten to mention that a few times in my life I have seen a battery short-out inside itself.

Check the Top of the battery with a continuity meter to check for that.
One of the strangest things I've ever seen, I tell ya.

The other thing you can try and make sure the top of battery is covered with a damp cloth.
If you have anything that takes power with the key off,I remove the fuse for that circuit.
Then I disconnect the + battery cable and very lightly touch the post to see if there is any abnormal current draw by seeing a little spark.

This method has been known to work.

* Please NOTE
A lot of people say NEVER do this, But I think I prevent the possibilty of battery gases from exploding by having the damp cloth.
I've done this many times on troubleshooting and I've never blown up.

* Disclaimer :

Poster removes himself for any responsibility for the blowing up of the battery, * grin *

Dennis

 

This "myth" about exploding batterys comes from the fact that a battery being charged very fast realeases hydrogen gas, which is combustable. If the battery is not being charged there should be no problem with sparks. I personaly have used this spark test method to check for shorts for years and have never had a battery "explode".

 

https://www.ford-trucks.com/dcforum/User_files/mil1ion/3bd3bd3979e94d61.gif
You should have seen all the feedback on the newsgroup alt.autos.ford when I suggested this method of finding current drain.
Cripes the board lit up like the 4th of July.
They actually thought that I had no idea what I was doing when I suggested it.

Now, I post a disclaimer and my experience doing it.

The guy ended up doing what I suggested and found the problem in 15 minutes.He left the light on in the box with a canopy on it.
Of course it was light when he parked it ,but the engine wouldn't turn over in the morning because the battery was dead.

He said he put a sign on his butt saying " Kick Me "

Dennis

 

My whole life I have been hearing warnings about exploding batteries caused by sparks. Usually something about sparks from jumper cables. That is why people always say to connect the ground to the engine block. I guess there might be some validity to this one because when you are jumping a car the dead battery will be charging very fast and releasing hydrogen after the engine starts. If any batteries were to ignite they would do it when the jumper cables were removed. I have never actually known anyone who had this happen to them though.
I also doubt the exploding battery theory because i don't believe that there is very much hydrogen being released even under fast charge conditions, because the hydrogen has to come from the water in the battery. If there were much hydrogen being produced then you would be loosing water from the battery to the tune of 18 grams for every gram of hydrogen produced. Or something like that. If anyone has a general chemistry book handy they can see exactly what is going on with the hydrogen by looking up the reversible oxidation/reduction reaction for a lead acid battery. What's the matter? Don't remember your high school chemistry so well? Well, neither do I, just enough to get into trouble. Which brings me to my disclaimer. Don't change your lead acid battery handling procedures unless you fully understand what you are doing.

 

When you are checking for current drain on the battery, turn everything off and don't forget to shut the door and/or disable the hood light. The interior lights/gongs & hood light current load will fool you during testing.

Chris
'88 F350 XLT Lariat CC DRW/7.5l/C6/4.10
'93 Mustang LX 5.0l/T-5/3.55's/Flo's/pulleys/K&N/Synthetics
Nissan p/u (DC commuter)
Volvo 940