'66 GTO Turn Signal question
 

Hi,
Not being one of great electrical knowledge, I need to ask a question, in hopes of learning, as well as fixing the problem.

The problem is that when the turn signals are on & flashing, the "Voltmeter" is bouncing back & forth between about 12+ volts, back to about 10 volts, each time the light flashes. And continues to do so, until the turn signal is turned off.
What could be the cause (hope it's simple), and what could be the fix/repair?
As always, Thanks for your help.

Allan

I assume this is with the engine off. Fully charge your battery and try again. How many bulbs do you have on each side? To me it sounds like your battery is either low on charge or it is on it's way out. Unless you have a high amp draw that seems like a large voltage drop.

Opps....Actually with the engine running.
Also, battery was fully charged, and had been on battery tender.
1 amber front light, & I think 3 bulbs in rear red lens

Thanks,
Allan

The battery feed thru the firewall to the turn signal switch could use some improvement, or the instrument ground is poor. Try adding a ground from the instrument metal to a dash ground as a test. Also make sure your firewall to engine grounds are in place.

George

With the engine running the battery voltage should be over 14 volts. Close to 14.6 volts. Sounds like charging system is not working.

Mine does this (although between 12 and 14v) when my turn signals are on. I've never worried too much about it. The more important issue is making sure your charging system is running at 13.8-14 volts when the engine is running.

My 65 did the same thing you describe when the turn signal was activated. As an experiment run a wire directly from the battery to the voltmeter. Start the engine. Activate the turn signal. If the voltmeter holds steady, then you are getting a voltage drop in the wire harness. Even if the connections and grounds are good there will always be some voltage drop in the wire harness. This drop can affect the voltmeter reading. What I did was purchase a small relay from Auto Zone. Ran a wire directly from the battery to the relay which I installed under the dash. Ran wire from relay to voltmeter. To activate the relay, I hooked it up to the accessory feed on the wire harness. This feed is only activated when the key is in the accessory or on position. My voltmeter now holds steady at a little over 14 volts even when turn signals are activated and even when the blower motor is activated. It just gives me piece of mind seeing the voltmeter hold steady and not jumping all over the place. Hope this helps. Good luck.