Need a little help/advice ASAP

[ghunt]

OK...This is one of those Murphy's Law things, what a surprise.

Anyway...

Had a guy call me earlier that wants to fly here from Boston tomorrow evening to buy my truck. A couple hours after I talked to him I figured I'd try to clean it up a little more and get it ready.

I ran out to put a couple gallons of fresh fuel in it (the stuff that's in it is still summer blend and it's supposed to be cold tomorrow). At some point during that trip the battery light came on and it won't go off.

I can't figure out exactly WHY it's on...I put a multimeter on the cable going from the alternator to the battery and I've got full voltage there. The truck had been sitting for several weeks and I went out and glowed it for 15 seconds and it fired right up, didn't crank slow or anything. I let it sit and idle and put the high beams on and everything and the voltmeter doesn't even look like it's budging. What's going on???

I need to get this figured out before tomorrow evening since this guy wants to drive the truck clear back to Boston!

 

[GOOSE]

Try checking the connections. I had to buy a new pigtail for mine.

 

[franklin2]

Measure the voltage on the battery with the truck running. It should be around 13+ volts if it's charging. I noticed on mine when it's charging well, the volt gauge is the dash is straight down. I have the original alternator system, and it charges around 13.7-14v. I believe some of the newer alternators run a little higher, around 14.5v when charging.

 

[ghunt]

I checked across the passenger side battery terminals and it was showing around 13-14 volts, the same as I was getting on the alternator cable. This was while it was running.

The needle on the voltmeter is pointing at the left side of the M in Normal, which looks pretty...well, normal to me.

I'll check the other battery. It just seems really weird.

 

[OnDaRoad]

Check the connections at the alernator

Check the connections at the alternator

Check the ground strap

Check the connector going from the alternator to the voltage regulator

Loose wire at the top of the alternator will result in the battery light
staying on ....


Jim

 

[franklin2]

I would take the plug off the alternator and clean it, and make sure the connections are good.

 

[FORDF250HDXLT]

after sitting for a couple weeks in the cold,that can be normal.take her out and run her for a half hour.i bet she fully charges and the light goes out.
i like to start with baby steps lol.

 

[ghunt]

Well it just seems odd that it came on WHILE it was running but wasn't on before.

I left the house, drove about a half mile to the gas station, left it idling while I put a couple gallons in it, and when I got back in the light was on.

Maybe I will drive it around a bit tomorrow...the guy isn't getting in until 7:45 so I have some time.

I'm doubly annoyed right now because when I went to check the connections on the batteries I found out the terminals on the positive cable were VERY corroded. I had a cable I bought a couple years ago but never put on, and I had hoped to sell it, but I had to put it on (and fought with it for two hours) and that didn't make the light go out either.

uggghhhh.

I'll check out the alternator wires tomorrow evening as well.

 

[plywood]

The battery light comes in in the case of a discharging system, or in the case of a charging system.

Two batteries take a long time to charge up, I think I would put the battery charger on it for a few hours or overnight.

 

[ghunt]

If I hook up the battery charger with the batteries in the truck, should I connect it to the passenger side battery or driver's side?

 

[subway]

if your connections are good it does not matter, the wiring will distribute the charge to both.

 

[typ4]

The light will not come on if the alt is working, dead batts or not.
Maybe the brushes are sticky, what alt is it?

 

[franklin2]

He is charging, he measured the voltage on the batteries. I agree with one of the other posters in this thread, I have had the wires get loose on the alternator plastic plug, and make the light come on, even though it was charging.