Electrical Problem 86 Bronco 302FI
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Joined: Sep 2001
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Electrical Problem 86 Bronco 302FI
I have an 86 Bronco XLT with the 302 FI. Something has been draining the battery if it is parked for more than 24hrs. Nothing is on and I replaced the battery and it still happens. I checked all wires that run through the fuse block in the cab and there is no current draw. With everything turned off I see a .17mA draw going down a fuse link from the terminal block. The only wiring diagram I have shows all wires from this link going to the alternator...can the alternator be drawing current and draining my battery? does anyone have a better wiring diagram that shows where else the current may be going?
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Joined: Sep 2001
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Electrical Problem 86 Bronco 302FI
I own a 1985 F350 one ton as well as Bronco and was having the same problem. I tried everthing and then one day remembered something from years ago I unplugged the voltage regulator and the battery never drained. I have since replaced the regulator and dont have any more problems. This could be your problem maybe
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Electrical Problem 86 Bronco 302FI
I had the same problem with my 85. It wasnt an electrical problem though. This one was moron related. You probably already have checked this but make sure your interior light is not on. Its hard to see in the light. I drained 2 batterys before i caught this. You might also want to check your glovebox light.
But hey what can ya say. We all act like morons more often then we would like.
But hey what can ya say. We all act like morons more often then we would like.
Laughing Gas
Joined: Jul 2001
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From: Bismarck, ND
Electrical Problem 86 Bronco 302FI
Well, since we're on the subject of electrical shorts, I've got one to throw out. I haven't had the time to trace it, so I'll look for possible feedback from anyone who may have had the same problem. On my '85, I have started having a problem where I will press the horn button (the horn works) and the radio will lose power. It will regain power, again, when the horn button is released. I'm imagining a short in the steering column, where the horn is somehow drawing power away from the radio circuit. What is confusing is that the horn circuit is "hot" all the time, while the radio is switched ("accessory" circuit), but this may not mean anything if the two circuits have wires that may have crossed and chaffed. No blown fuses as of yet, but I haven't measured the amperage draw..... it may be borderline. Not a huge problem, but if anyone has had a similar experience, I'd welcome the input!
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Electrical Problem 86 Bronco 302FI
jeffn8971, if one or more of the diodes in the alternators rectifier bridge are shorted, they will drain the battery when off. Current will flow backwards from the battery through the heavy wire to the alternators output, through the shorted diode to ground. If you have the stud type of heavy wire connection on the alternators output, put your ammeter or test light in series there to see it.
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