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Posted on Apr 14, 2009
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Volts drop off while driving and then go back up

I will be driving down the road and my volt meter will read close to 14 volts and then all of a sudden I will feel a slight power loss and the meter will go down to about 9 volts. Then out of the blue is will jump back up to normal. This usually happens when I am driving with the lights, heater, or radio on. I took the altenator off and took it to Autozone and they told me it was fine

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  • phxmark123 Apr 14, 2009

    Thanks, I will take the whole vehicle down to auto zone and have them check it. That would be great if it was just the battery. I haven't replaced the battery and it has given me trouble before when the truck sits awhile

  • phxmark123 Apr 14, 2009

    Is the fusible link that is on the firewall a fuse holder with a fuse in it? Because if it is there is no fuse in mine

  • phxmark123 Apr 14, 2009

    I found the fusible link by the altantor and it looks good. I put a new altnator on and now my volts on my dash read about 9 volts all the time and wont change. Took the truck back to Autozone and tested the battery and it is good. The voltage at the battery is 12.3. and stays steady there. I think it should read higher though. Almost like it is charging good but drawing current somewhere. When I put the altenator in I redid all the connections to make sure they were clean and tight. But overall now it is worse.



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Chk. all your connections to the battery make sure there clean and tight, and also to the starter, and all other ground connections like from frame to engine to body. I know you said auto zone chk. it and said it was ok but it still sounds like the internal regulator is kicking in and out to me, but a loose connection could cause that to.if you chk. everything i sugested, and find no problem, find a shop that specializes in alt. rebuilding and have them chk. it they know a little more than auto zone does, its there business.

  • Anonymous Apr 15, 2009

    The battery itself will only show 12 volts, What charge rate does the alt. show when its running, did they hook it directly to alt. to chk.what alt. is putting out when its running? it should be around 13 to 13 1/2 . Also your guage in the truck could be off a little. When you tax the system, thats means everything on thats electrical can you hear the alt. singing if you do the alt. is working. Voltage at alt. will drop when taxed thats normal, but not more than a volt or two. You might want to install an aftermarket volt meter thats more accurate than the stock one in dash.

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  • Posted on Apr 14, 2009
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You could have a dead cell in your battery or one or 2 cells that are going bad, its sometimes difficult to check depending on what kind of battery you have in the vehicle. Another option is to check on all you battery leads and wires that run from the alternator, make sure they are free from corrosion and grime. They need to be tight enough that you can get no movement from them with your hands.

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