So, as the title says, my battery gauge fluctuates when the turn signal is blinking. What causes this and should I be concerned?

Mine does the same thing. The lights add load to the battery causing the voltage to drop which makes the gauge move a little bit. IMO, it's normal.

The is voltage not current and the turn signals don’t drop the voltage far enough for the gauge to respond. I’m guessing voltage difference with the lights on compared to off is a fraction of a volt and the gauges aren’t that sensitive.

What’s probably happening is a corroded connection in the circuit somewhere. The ground is common for both the turn indicators and voltage gauge on the dash. If the connection to ground is corroded, when the turn signal indicator in the dash comes on, it takes a way part of the ground for the voltage gauge making move. This is very common because the connection to ground for the printed circuit board corrodes easily (common to most GM cars of that era). Fortunately it’s a pretty easy fix. Getting the dash out is pretty easy and the connection on the printed circuit cleans up easily as does the connection on the connector. Clean them up and I’ll bet it goes away (no warrantees).

I have a similar situation going on, only I have more symptoms.

My front signals work, my front SIDE markers work, my rear signals work (both bulbs on each side), but my rear SIDE markers do not. I have cut the lamp socket on both (corroded anyways and needed replaced) and with my volt meter was not getting anything.

Strange thing is I hooked the volt meter upto the positive terminal on my battery and probed for ground. Nothing. To be expected if the ground is bad. But then I hooked up to the negative terminal and probed for possitive. On each side , BOTH wires gave me a reading.

Now, it was late and I was tired from redoing the rear brakes so maybe I was not paying attention....

Most of this is probably diminished grounds. Battery to engine. Engine to chassis. Harness to chassis grounds etc.

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Rodney Dickman

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quote Originally posted by Rodney: Most of this is probably diminished grounds. Battery to engine. Engine to chassis. Harness to chassis grounds etc.

Yup... Check grounds and + box under c500 (84, check fuse links at starter...)

See my cave, wire service in electrical section.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

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