Charging Problem - '89 Bronco II

I'm hoping someone can help me: I have a 1989 BII, 2.9 V6, manual trans, that is not charging. It was charging and then intermittently wouldn't charge, now it doesn't charge at all. If I charge the battery it stars right up & runs good - just won't charge. I had the old alternator checked at a NAPA store that I trust & they indicated it was good - no need to be replaced. I swapped the battery with one out of another vehicle that I have - no change. I checked all the ground wires/battery cables - no problems found. I took it in to a local shop that knows BIIs - they couldn't find anything wrong (that's when it was charging intermittently) and they said that maybe the alternator was going bad. I bought a rebuilt alternator and the "squarish" 3 wire connector and installed them both (soldered the new connector to the old wires) - no change. I even replaced the ignition switch (the electrical one on the lower steering column) because at one time it appeared that when I wiggled the ignition switch that it would charge, then not charge. That didn't fix the issue either.

I'm about at the end of my rope here - does anyone have any ideas on what else to look for or check?

Thanks - Tim

Man, this one's a head-scratcher, and welcome to TRS. You've already done just about everything that I can think of, so what's left? I know that you said you checked the wiring, but the only other thing that comes to mind is a weak or corroded connection. Did you unwrap, and open, the wiring harness looms so that the whole wire run was checked; and what about looking under the power distribution box for corrosion, especially under the two 60A fuses, #3 and #7?

the three wires in the plug are as folows: Batt' supply(high amps, heavy gauge wire/s), Voltage sensing, which is just a loop from Batt suply back to the regulator, and then switched power. Without switched power, the alternator wil not "power up" during the start up of then engine, and thus will not produce and output. The alternator its self could be fine, thats why when it was tested, it passed. After startup, alternators are internaly powered, this is where the voltage regulator wire is important, if its fawked, then it will also cause erattic or a flat out no charge situation. Check to make sure you have Voltage going to the "I" termanal when you turn the ignition switch to the on position, it should read 12 volts. Dont use a test light, all they are good for is scratchin yer balls and cleaning your fingernails. If you have ignition supply voltage, you need to check the alternator outputs. First, start the truck, and use an amp clamp to see what the output of the alternator is at idle, make a note of this number. Then, you need to hook up a load tester and load the system down to 13.5 volts. IF you dont have one, you can try turning all your lights on and your heater fan, this could put enouh load on the alternator to satisfy this test. After all that, use the amp clamp to get a high idle(1500rpm) amp output. This # should be later then the idle ampers, if not, the regulator is screwed. btw, crarging voltage should be no more then 14.6ish, and no less then 14, if it is, then the regulator is slowly dying. The alternator is pritty much trying to force amps into the battery, voltage is what pushes it, if the charging voltage is low, the there wont be enough voltage to overcome whats stored in the battery, and all is lost. This is kinda long winded, so first, check the Ignition feed termanal Key on, power, key off, no power.

Charging Problem Solved!

After checking the things recommended (thanks guys!) I still got nowhere. When that happens, I tend to start over from scratch just in case I missed some detail the first time around. I took the new (rebuilt) alternator back to Napa & had it checked & it was defective! They ordered another which I was able to install last night & all is good now.

I guess the lesson learned is just because something is new doesn't mean it'll perform as it should.

Cheers,

Tim

Thanks for letting us know what you found. That was a good idea, going back over everything, and really glad to hear that you got it squared away.

Ya, thats a key thing, just cus its new, doesnt mean its good.

I had a starter from napa like that once. It would randomly just "click" when I tried to start. They tested it and it was fine, told me I needed to run a second ground wire. Yeah, ok, My 2002 F-250 needs a second ground. I bitched until they gave me another starter and all is well since.

It Happens.....

I've always had really good luck with NAPA parts - better than most other parts stores. I live in a mountain community where we have 3 choices for auto parts and NAPA is by far the best IMHO. The guys that work there are very good at what they do & I'm not going to let one little snafu keep me away. They made it right - right away with zero questions. Ya can't ask for much more that that I guess.

I’m having the same issue now. I’ve gone over the wires I pulled the wire harness out to the alt and taped it back up. I’ve charged my battery up to 12.6v and ran my truck and it’s dropped all the way to 12.3 while on and 12.0 to 12.1 volts currently but is slowly dropping.
I drive an 87 bronco ii