Anyone know how to test an ammeter/voltmeter in the vehicle?

[k20]

I dont know if you can test it or not. Also not sure if I have ammeter or voltmeter (i hate electrical lol) on the gauge it says 8 13 18 (i think those are #'s), which gauge is it, and is there any way to test it? I dont know if its my gauge or if its my alternator. MY gauge randomly dips down to near 8 then springs back up to 13 and runs there alonggggg time then will dip down again. Usually only if im runnin a constant speed, like down the interstate.

 

[diesel4me]

Sounds like its a voltmeter--it could be you have a short curcit,like a wire pinched to ground momentarily,causing a big drain on the altenator and battery,making the needle take a nosedive--could be the altenator or the printed curcuit board that the gauge gets its power from,or the gauge itself too. /forums/images/graemlins/crazy.gif

 

[big83chevy4x4]

yep you have a volt meter.

one way you can test the guage is with the ingition in the on position and the engine off, grab a voltmeter and see what the battery is at for voltage. the guage should be the same. if the guage fluxuates like when it is running, then its the guage or wiring for the guage.

 

[gatorbait]

sounds like a voltmeter. Easy to verify battery voltage with a handheld multimeter. Volt gauges are cheap and easy to wire you might just replace it.

 

[k20]

ok, I just did your test, the gauge didnt fluctuate, but it didnt seem to read what the voltmeter did. The battery showed about 12.6v, and the gauge was reading between 11.5 and 12 (not the most accurate gauge to read lol). My lights dont dim or anything when the gauge nose dives, so im at a loss.

 

[big83chevy4x4]

did you put the voltmeter on the batt with the engine running? it should be about 13.5-14 volts with the engine running.

 

[k20]

yeh thats what it is at running. Im thoroughly puzzled by it lol.