Help! Battery gauge drops to Low

So the other day I was up at the mountian, Truck was running fine all that day. Stopped and grapped a bite to eat, Started up the truck, turnd the heat on because it was 29 degrees outside, turnd the 4x4 on, and all my light's. Then I look at my battery gauge and it's almost to the L on the gauge. so I turn everything off and then back on and we're back on the road again. That was 5 day's ago and it's been running great ever since. Then as im pulling into my driveway just a few minutes ago I look at the gauge and it was almost at the L again! I also noticed my dash light's dimmed and the truck's steering was stiff. Im thinking alternator or battery. I don't know how old the battery is because I bought the truck used 2 years ago. Could anyone help me determine what the problem is?

1999 XLT SOHC 158,000 Miles

Thanks,

-Russ

Get a voltmeter and start reading voltages -- you should be able to narrow down which part needs to be replaced by testing parts and removing parts from the system.

Thanks, Where do I stick the voltmeter to read the voltage on the alternator?

There is a big wire going to the alternator -- that is the positive (sometimes has a rubber boot covering it).

The body of the alternator is ground (or anywhere else on the engine, chassis, or body that is steel).

You can probe it at either the alternator or battery.. If you probe at the alternator careful not to hit any other connector to prevent a arch. You should be putting out atleast 13.0 volts DC current with the engine running.

Your steering was stiff too? Hmmm... Is your belt tight?

Cobraguy said:

Your steering was stiff too? Hmmm... Is your belt tight?

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Pretty sure yeah. I just replaced it a couple month's back and the tensioner was in good shape. Im just losing electrical power when I have my light's and heater going for some reason. Ill check the belt later on and hook it up to the volt meter. I would do it now but it's 32 degrees outside right now. lol

The reason I mention that is when you load the electrical system, you load the alternator. If the belt slips, it will drop your voltage and your steering will stiffen. But man...I haven't seen a serpentine belt slip like that. It would have to be pretty bad. But with what your telling me, that's where I would look.

Well, I know we have a voltmeter around here somwhere but didn't have any luck finding it. So I checked the belt and there is some play in it. It doesn't seem like enough play to where it would slip though. I also cleand the battery terminals because they were pretty dirty. I took her around the block and it was fine in til I pulled in the driveway, The gauge is normal intil I turn the steering wheel and then it drops. Aloso the weird thing is just sitting at an idle with the heat and all my light's on it's fine then I turn the windshield wipers on and they are wayyy slower than normal, and then the idle jumps up to about 1200 RPM from the normal 900 or so RPM at idle. You still think the belt is a possibility?

Well I just had the battery and alternator tested at the shop I used to work at and they both passed. He said I most likely have a worn out tensioner. I feel alot better now. haha thanks for your help.

-Russ

Same thing happened to me in my 91X about a year ago. I was driving and saw the volts drop, and like a dummy I kept driving it like that. This happened while we were camping and about 5 times over the weekend I would see the needle jump up to normal for about a mile, which I guess was enough to keep us running. We ended up making it back home and once in the driveway it wouldn't start again

I replaced the alternator and it was good to go for about a week until the battery died on me as well from all the strain of the dead alternator.

In your case if your steering is tough I would agree that is probably your belt

Well I replaced the tensioner and it did not work. The belt doesn't have anymore that 9,000 miles on it so I wouldnt think that would be bad. It look's fine. It's wierd...When I turn my light's and heater on it's fine then when I turn my steering wheel it goes down to the L on the gauge. Not all the way down but close. Also when it does do that the idle jumps up to 1200 RPM from the normal 800 RPM or so. Then Ill shut it off at night when I come home, Start it up in the morning and it idling at like 1600 RPM???? What is going on? Anybody have any other idea's? Alternator and Battery both tested good.

Thanks,

Russ

Well I went ahead and replaced the belt too just in case, and it didn't fix it either. so I went and had my battery & alternator checked again from a different place and they said my alternator is good but my battery is getting weak. But this is coming from a place that only does batteries & not alternators so i'm not sure to believe them or not. Any Idea's?

Alright now I have spent over 100.00. I replaced the Tensioner, Belt and Battery and it's still doing it. is it the alternator you think? Please help me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

after replacing the tensioner and belt, is your steering still stiff?

No but it wasnt stiff all the time before. Just when I had my heat, and light's on then I would turn the wheel and it would be kinda stiff feeling. It stopped the wierd Idle thing it was doing. Now the gauge just drops a little bit when I turn everything on. And the lights dim a little too. Is there anything else it could be other than the alternator? I think ive pretty much nailed everything else lol ??????????????????????????

anyone? Please! Im kinda freaking out here because it's my only transportation. I replaced battery, belt and tensioner. could it be anything other than the alternator? I don't want to spend a couple hundred dollars on one and find out thats not what it was.

It really sounds like you nailed the problem already. If it's only dipping a little now, with everything turned on and no more low idle speed, I'll bet your alternator's fine and you just may have some corrosion inside of one or both of the battery cables. If you find your volt-meter, use it to check the voltage at both ends of the hot wire between the battery + and the alternator and also between the battery and starter solenoid. If you have more than about .2volts difference, there is significant resistance (loss) inside of the cable. Check the neg cable too, positive probe of the voltmeter on the pos. battery post and then with the neg probe, check both ends of the neg cable for a difference in voltage. If so, that could account for the dip and the lights dimming a bit.

when the steering gets stiff does the rpm of the engine change too ?
could be like mine was, , the engine just settles down to too low of rpm and the belt is not turning fast enough , i checked and had a bad plug , i changed it,, the problem went away ,
any trouble codes , or is the check engine light on ??

corkey said:

when the steering gets stiff does the rpm of the engine change too ?
could be like mine was, , the engine just settles down to too low of rpm and the belt is not turning fast enough , i checked and had a bad plug , i changed it,, the problem went away ,
any trouble codes , or is the check engine light on ??

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Well after I replaced the tensioner and belt the steering and idle has been fine. Now when I turn my heat on and turn the steering wheel the battery gauge fluctuates a lot. If I am driving or rev it up it's fine. Only at an idle. which makes me believe my alternator is getting weak. don't you think? My plugs and wires are new. I don't know what else it could be?