I've been having problems with my '97 for about 4 months now with charging. At first I thought it was the battery so got a new one. It died after a couple of weeks, so I wipped out the multitester and started checking what my Haynes manual suggested.
But first, the charge light comes on intermetintly(sp?) and sometimes it stays on all the time.
Anyways, I checked the alternator, it was fine. I just changed it about 3 years ago. So I started checking other things like wiring. I had changed the positive battery cable 2 years ago so I checked the negative cable. Sure enough the insulation was cracked down by the starter and the wiring was corroded. I thought I found the problem. Due to $$$ shortage I taped it up and just kept an eye on the battery. I also had shoulder surgery in the meantime and could not work on anything.
Last week thetruck suddenly stopped starting, it would only click. I thought it was the cable so I antied up the $$$ and got one. Brough it home, slapped it on and...........nothing. So I took the starter off and sure enough it was bad. Figured it was my whole problem. Took it for a drive today, with a fully charged battery. After about 10 minutes the charge light came on. It is now doing the same exact thing it did before. It went off, then flickered then came back on and stayed. Later on it was off, flickered on and off a few times and eventually came back on for good.

Does anyone have any idea what I should look at now? I'm going to recheck the voltage regulator, power distribution box and the ALT fuses along with the alternator wiring. Beyond that I don't know what it could be. I hope its not the alternator after just paying $207 for negative battery cable, stabilizer bar link(2nd one I've had broken in last 5 years) and bushings and another $104 for a starter. This thing is bleeding me dry as of late and with me off work recovering from surgery, luckily I'm back to work Monday.

Anways sorry for the long post but I would greatly appreciate any and all help.

 

I know you said that your alt is fairly new but, hypothetically speaking:

Lets say your alt is charging but at a lower voltage under load such as around 11v or 11.5v. What I mean by under load is when your driving down the road or reving at aroung 2k - 3K RPM. Not in the yard at idle.

That means the Battery will be sitting in the truck, not fully charged most of the time. This will kill a battery in a matter of months depending how much below proper full charge it sits at.

Then When you start the truck, with the battery charged to 11v the lower voltage availiable to the starter means a lot more Current (Amps) to compensate. Thus overheating the starter every time you start it. Eventually it will burnout your starter.

Or

The ALt may be overcharging, also not good on the battery and weakens it so that it can no longer accept a proper charge.

So myslef, I would make very sure that I eliminated a possible Alt defect and go from there.

I hope all goes well for you and your shoulder.

Dpostman

 

Thanks for the advice. I'm beginning to think it might be the regulator but I'm not for sure. I checked it today and went over everything the Hayne's manual has listed for battery/charging.

When I started the battery with engine off was at 12.21 volts and the charge light was on.
I had already driven this morning for about 20 minutes and when I started(engine cold) the light was off, after 5 minutes(engine warm) it flickered on and off and eventually stayed on.
I tested the regulator to battery positive post= 12.17 volts
I tested regulator to chassis ground= 0.0 volts
I tested Alt Field Fuse to regulator for resistence= 1 ohm
I tested the Alt Mega Fuse to battery positive post= 1 ohm
I connected a jumper from the regulator to the battery positive post; Hayne's manual says if battery light flickers the regulator is defective. I had no battery light at all. This is done with ignition in on position but not started.
I checked the Alt Field Fuse, fuse is fine.

After all this I decided to start the truck and check the charge rate. When I started it the charge light was on and sure enough at the battery I was only getting 11.72 volts at idle. I then reved it up to 3-4000 RPM (thus far being under load or at idle has not seemed to make a difference) and the voltage dropped slightly to 11.70 volts.
I then wiggled all cables and wires and the voltage remained constant. So I shut the truck off and rechecked the voltage on the battery, 12.01 volts. It had dropped 0.2 volts since I started.

Also the first 2 weeks after my surgery I couldn't drive so my truck just sat. When I went to finally start it the battery was dead. I really think there is something draining the battery but I don't know where else to look.

Edit: one other thing. When I had checked previously, if the charge light was off the alternator was charging the battery at 14.4 volts. So when the light is on the charge rate drops around 2.7 volts from when the light is off.