Dancing Battery Needle

[pgackerman]

Noticed my battery gauge needle dances down and back up when my blinker is on.

Does anyone else's do this? 

[Slyp]

A short???

[GTRS Fiero]

Dances?  When your blinker blinks, you can see it on the volts gauge?

If so, that should not happen.  The blinkers should not draw that much current.  You may try testing the hazards, to see if the issue is isolated to the blinker system or not.  Then check the parking light.

[Slyp]

Also when it happening take a look at the lights and see what they are doing.  Does this happen only with the turn signals??   If so try right then left and see what the lights are doing.  Need to get out and look at the lights when it is happining

[GTRS Fiero]

Good point.  Yes, turning on the blower motor would be a good test to check for a failing voltage regulator or alternator.  The blower motor draws more current than the blinker.  If the draw is excessive, you may have your answer.

[Raydar]

I hate to be "that guy", but maybe you have a grounding issue. Or other sketchy connection.
But I have seen that same thing. It's been a while. Seems like it was after I installed my underdrive pulley on my 3.4.

[GTRS Fiero]

So you probably saw it at idle.  Out of curiosity, did you replace the alternator, also?

The easy way to check for ground issues is to add a temporary ground to each light, one at a time.

[Fierofool]

At idle, both my cars' voltage meters will fluctuate a little.  Always have.

[pgackerman]

Noticed initially when I was stopped at a light.  Needle moves with the blinker.
Noticed again while changing lanes.

Been told by a reputable source that the regulator on the alternator is going and I'll probably have to replace the alternator.  Not a big deal except getting the belts tight. 

Find it interesting that the needle is above 13 when the car starts and stays there, or at 13, for quite some time.

[GTRS Fiero]

The alternator should produce between 14 and 14.5 volts.  As current is drawn, it will compensate a bit.  Since current is always being drawn, the gauge will read a bit lower.  When you turn on an accessory, it draws more current.  If the alternator cannot compensate, as in the accessory is a higher-amperage item like a blower, you'll see a voltage drop.

For people with a power pulley, I'd recommend a higher amperage alternator.

I realize that you know this, but maybe it will help future readers.

[Fierofool]

Starting the car draws a lot from the battery.  The alternator will kick up the output when the engine starts and the starter is no longer engaged.  It might go up to 14 Volts, or more, but settle down as the battery is recharged.  My gauges run at about 13 Volts when idling or running down the road.  They don't change with engine speed.  Turn on an accessory like the heater or AC and it will drop down to 10 or 11 at idle and gradually move back up just below the center mark. 

Once I start moving at higher revs, the gauge will move above the 12 Volt mark and will fluctuate a bit as the AC cycles.  As long as it keeps the battery charged, I don't plan to replace the alternator.  I just don't see a need. 

[GTRS Fiero]

Fierofool, yours sounds about right.  I do test my alternator regularly.  Mine normally runs just past the center mark.

[GTRS Fiero]

Pgackerman, did you master your Fiero's tango?

[pgackerman]

Still starting, still running.  Even with A/C and blinker on.

Using my car as a daily driver this week and maybe next.  Maybe I'll get some garage time around father's day.

[GTRS Fiero]

Any update?