Voltmeter bouncing while turn signal on (1 Viewer)

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This has been on my list of things to fix but a low priority item. As I am nearing it on my list, I wanted to get some advice from y'all. Might this be a failing alternator or faulty wiring causing the voltmeter to bounce like this when using the turn signal?

 

OSS

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It's normal. Mine did that too. It doesn't mean anything. The volt meter also acts sort of like an amp meter- the needle will drop a bit when accessories are turned on. Just another charming quirk of the FJ60,
 

Seth S

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The voltmeter drops when stuff is turned on because you are using more voltage. The charging system is adequate but not massive so if everything off the alt outputs 13.5 volts..it might dip to 13 with stuff on. One thing that can help is to put heavier gage battery cables in between the alternator and battery and add more heavy gage grounds between the block, body, and battery as well as beef up the positive battery cable.
 
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My 89 did the same for 10 years. Last July I finally replaced all the OEM Battery Cables with new set from @forrunner. Solved the issue.

Thanks, ill


The voltmeter drops when stuff is turned on because you are using more voltage. The charging system is adequate but not massive so if everything off the alt outputs 13.5 volts..it might dip to 13 with stuff on. One thing that can help is to put heavier gage battery cables in between the alternator and battery and add more heavy gage grounds between the block, body, and battery as well as beef up the positive battery cable.

I was thinking about upgrading everything and this makes sense. Now I just need to look into updating my fuse-link wires, as well.
I’m assuming this will address some other oddities which I’m experiencing within the electrical.
 

Seth S

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Thanks, ill




I was thinking about upgrading everything and this makes sense. Now I just need to look into updating my fuse-link wires, as well.
I’m assuming this will address some other oddities which I’m experiencing within the electrical.

New wires done properly should help. The harnesses in these trucks are old. As the wires age and flex and heat cycle they wear. And they build greater internal resistance.
 

Spook50

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It's normal. Mine did that too. It doesn't mean anything. The volt meter also acts sort of like an amp meter- the needle will drop a bit when accessories are turned on. Just another charming quirk of the FJ60,
Yup, even after doing the "big 3" electrical upgrade it still fluctuates. What I'm curious to see is if it does it much when I swap over to LED turn signals and do the timing mod on the OEM 60 flasher.
 
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Fixed mine by adding an extra ground from the battery to the chassis. Easy to check with a jumper wire before you clamp it on.
 

Spook50

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mine does it too, high output alt, dual batteries no biggie
Mine's also a 120A. I have a NIB OEM 80A as a backup in case of an emergency, but my 120A has held up very well since replacing the voltage regulator and rectifier with Denso parts. Next mod I want to do for it is an external rectifier. Look up the Quicktifier. Very slick setup that I can mount right near my Mallory box on the driver's side. Supposed to handle high (near-capacity) draws very well as opposed to the internal rectifier which can overheat and burn out diodes.
 

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