14 volys at batt and alternator, guage says 12 volts???

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Erik Beckett

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Joined Apr 6, 2001

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710 Posts

Discussion starter · #1 · Jul 21, 2003

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So I was doing some trouble shooting this weekend on my electrical system and i am lost. I was told to measure the volts at the battery and the alternator with car running and all my lights and fan on and see what the volts say. I have been having a problem with the volts dropping down past 12 volts. So I tested and I get 13.9 volts at the battery, 13.9 volts at the alternator and 13.9-14 at the horn relay with everything on. the guage in dash stills reads 12 volts and sometimes flucuates lower and higher. What the hell? I don't know where to look next. Everything is brnad new too. Any more suggestions? I also ran the 8 guage wire direct from the battery to the alternator and now when I taop the brakes the volts drop.

 

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Brian Lewis

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Joined Apr 17, 2003

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2,108 Posts

#2 · Jul 21, 2003

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Check the ground your gauge is using??

 

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John_Muha

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Joined Sep 3, 2001

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523 Posts

#3 · Jul 21, 2003

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When you are doing your tests what you measure on the fuseblock BAT and IGN terminal? I assume that this is an aftermarket gage wired on the IGN side of the switch. If BAT looks good it’s not a ground issue. If BAT doesn’t look good it may be the forward lamp harness positive lead connection on the horn relay or a ground.

 

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dnult

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Joined Mar 29, 2002

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5,276 Posts

#4 · Jul 21, 2003

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Guage could be out of calibration also. Do the voltage checks as others have suggested. Best of all is to measure the voltage between the + - leads of the guage (wherever they may be connected). Many of the guages have a calibration pot inside the lamp socket. Just don't tweak it without checking though. If you do have an electrical system problem, a miscalibrated guage won't be of much use.

-dnult