Voltage drop on gauge

[Bri guy]

So when i use the blinkers the needle on the volts guage will bounce. When using headlights the needle drops to 12 on the gauge and stays. The wire from battery to alt is new. 10ga. New alt 2wire plug. The ground cable from battery to block is new. Power cable from battery to starter is new. Alternator tested good. What else can i do to stop the bouncing? Or is this kinda normal on older cars?

 

[melloelky]

@an idle or driving?

 

[fleming442]

Get a better battery and up the 10ga charge line up to 8 or 4.

 

[airboatgreg]

Hook up a voltmeter to the battery first to see what is going on

 

[Bri guy]

14.6 volts on battery and alt with 0 loads at idle.
Headlights with brights, fan on high and 1 blinker going and battery and alt were at 14.1 volts.....but the guage shows deep in the red and pulsed with blinker.

 

[Bri guy]

Going like a strobe light

 

[Bri guy]

I wonder if the guage or part of the wiring going to it is bad....if alt and battery are staying at 14volts with load..... but by the time it gets to the gauge it reads less than 10 volts...something between the alt the guage is the issue?

 

[Ribbedroof]

Do you have a ground from the block to the car body?

 

[Bri guy]

Do you have a ground from the block to the car body?

........i seen a ground from the block to the firewall. Would that be good enough? Looks like a little metal strap

 

[Bri guy]

Do you have a ground from the block to the car body?

Now that you mention it....thats the only 1 i have seen and not replaced. I moved the alt to the passenger side today. The meter reading is better after i moved the alt...but guage looks worse now.........seems odd.