Hello All,

The inevitable 2G alternator failure happened to me, so I replaced it with a brand new one. I avoided a rebuilt due to all the bad reports I've read about them. I had my battery checked and it came up strong. Almost everything seems to be working fine now, except that my battery indicator light is staying on.

My headlights are good and bright, even with the heater and radio full blast. The dashboard voltage meter is about where it should be, and the battery seems to be keeping its charge.

In addition to seeking general troubleshooting advice on this problem, I'm also looking for a link to a complete wiring diagram of the alternator charging system, including the battery light now stuck on, and the instrument cluster's voltage meter. I've found a few diagrams, but they are all lacking in some essential detail. For example, some have wire colors, but no indication of what pin numbers they are going to. I haven't found any that show the voltage meter.

I have a background in electronics, so I'm sure with a good circuit diagram, and some explanation of how the system is supposed to work, I could figure out why the battery light is staying on. Naturally, hands on tips from someone who's had this problem would be a big bonus. BTW, I have the Haynes, but it's no help in this case.

Oh, and the Bronco is a 1990, 5.8 liter, EB edition.

Cheers,
Tim

 

if everything is hooked up as it was before perhaps you got another bad alt. You might think about taking this time to upgrade to a 3G alt. they are a way better altenator and not prone to catching fire like the 2G units are.

RJM Injection Tech check this site for 160amp 3g Alt, they also have the proper wiring harness and everything for a plug N play setup. you will be way happy.

 

Kemicalburns:

I'd like to do a 3G swap, but I just don't have the time, parts, or cash right now. The alternator I got was new BTW, not rebuilt, though I suppose it's possible that a new one could be bust too. However, I'm really not having any operational symptoms that I can see; the battery seems to be staying charged, even with everything on, and the truck at idle. If that darn battery light doesn't go off though, how am I supposed to know when/if something is wrong?

 

If the battery is strong now, it won't be for long if the indicator on the dash is on and you run anything more than just the engine. Aside from getting a bad alternator right out of the box, you could have wiring issues. The charge indicator comes on any time the voltage from the alternator is lower than the battery voltage while the engine is running. So it either means the alternator output is low or non-existant or the wiring between it and the battery has a problem