F150 Electrical system

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  #1  
Old 08-05-07, 06:03 PM
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F150 Electrical system

I have a 1999 F-150 with the 4.2. Yesterday, the battery died while the truck was running waiting at the boat ramp. We got it jumped, but the voltage was at 0 as soon as we disconnected the jump vehicle, and it died again. I had to pull the battery out of my boat to get the truck in to town to get a new battery. After I put in the new one, they checked the alternator and it was working correctly so it seems everything should be ok, but... the battery light on the dash stays lit even though the dash gauge is right where it should be indicating the proper voltage. Also, the odometer no longer lights up. I've checked the fuses but haven't found anything wrong. Any suggestions?
 
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Old 08-05-07, 06:10 PM
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That battery light indicates a failing alternator usually, specially Fords.

I do not trust Autozone tpye alternator tests.

Inspect all your cables very carefully.
 
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Old 08-05-07, 06:26 PM
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Originally Posted by HotinOKC View Post
That battery light indicates a failing alternator usually, specially Fords.

I do not trust Autozone tpye alternator tests.

Inspect all your cables very carefully.
Which cables do you mean? The battery cables? There is a fusable link on the positive cable. What is that? What other type of test can I have done?
 
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Old 08-05-07, 06:36 PM
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A fusible link is a piece of wire with either a physical fuse or a specially made wire made to short out to prevent damage to the vehicle.

Yes, inspect your battery cables for corrosion/damage. It is quite common for battery cables coming from the alt --->starter---->battery to be bad.

How long did they run the alternator test for? I'm guessing it's the alternator, cables, or maybe a belt pulley problem.
 
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Old 08-05-07, 08:21 PM
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You might want to get the alt checked elsewhere (a second opinion)
The dash gauge is a general indicator, it can't tell you if it's up to specs
 
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Old 08-06-07, 04:40 AM
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I would guess the test was about a minute long. I guess I need to take it somewhere else. Thanks!
 
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Old 08-06-07, 05:55 AM
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Are you the same person having electrical problems in travel trailer in another thread? If so,then it sounds like the problems are related to both vehicles. Sounds like a short that has taken out some components in the truck and/or the trailer.
 
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Old 08-06-07, 10:33 AM
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Originally Posted by daswede View Post
Are you the same person having electrical problems in travel trailer in another thread? If so,then it sounds like the problems are related to both vehicles. Sounds like a short that has taken out some components in the truck and/or the trailer.
Yes, however I had the refrigerator problem with the trailer before hooking it up to the truck, and the truck is doing this without the trailer attached. Additionally, the battery had run down in the truck previous to my owning the trailer and I just have an idea that the alternator was good enough to keep the battery up until it had to supply enough amps to feed the trailer as well.
 
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Old 08-06-07, 06:35 PM
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I had the alternator re-tested and it showed 12.8 volts output, but only 3.9 amps. It sounds like it needs to be replaced doesn't it?
 
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Old 08-06-07, 07:17 PM
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12.8 volts is slightly low. The vehicle will only draw as many amps as it's need to keep things on. Example, if you have a alternator that can produce 120 amps, you are not going to get 120amps on your meter unless the vehicle is drawing that much power.

If you want to see if your alternator is producing current, turn on your headlights when you're parked and the engine idling with the headlights shining on a wall (at night). Notice how bright they are. Then turn the engine off. The lights should get dimmer when you turn the engine off. If the lights get brighter when you kill the engine, the alternator was not charging sufficiently. When doing this test, the lights should be the only load (turn the stereo, a/c and other accessories off). With a heavy load, an otherwise good alternator may not be able to produce sufficient amounts of current at idle.
 
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Old 08-09-07, 10:21 AM
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Well I replaced the alternator and it seems the problem is fixed. I put a circuit tester on the battery while the truck was running and was only showing 11.5 volts. Even though the test done at autozone and advance said it was ok, when I took the alternator off and took it to autozone for testing it failed. So, thanks to everyone for helping.
 
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