Reply
 
Thread Tools Display Modes
  #1  
Old 05-12-2025, 10:29 AM
oldman66gto's Avatar
oldman66gto oldman66gto is offline
Member
 
Join Date: May 2025
Location: St. Augustine Fl
Posts: 71
Default '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

  #2  
Old 05-12-2025, 07:04 PM
Goatracer1 Goatracer1 is offline
Ultimate Warrior
 
Join Date: Oct 2003
Location: NH
Posts: 4,265
Default

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.

  #3  
Old 05-12-2025, 09:35 PM
oldman66gto's Avatar
oldman66gto oldman66gto is offline
Member
 
Join Date: May 2025
Location: St. Augustine Fl
Posts: 71
Default

Quote:
Originally Posted by Goatracer1 View Post
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

  #4  
Old 05-12-2025, 09:46 PM
george kujanski's Avatar
george kujanski george kujanski is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: palatine, il. USA
Posts: 8,055
Default

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

__________________
"...out to my ol'55, I pulled away slowly, feeling so holy, god knows i was feeling alive"....written by Tom Wait from the Eagles' Live From The Forum
The Following User Says Thank You to george kujanski For This Useful Post:
  #5  
Old 05-13-2025, 08:41 PM
Goatracer1 Goatracer1 is offline
Ultimate Warrior
 
Join Date: Oct 2003
Location: NH
Posts: 4,265
Default

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

  #6  
Old 05-13-2025, 09:50 PM
1966Lemans's Avatar
1966Lemans 1966Lemans is offline
Senior Member
 
Join Date: Sep 2010
Location: Berlin, MD (near Ocean City)
Posts: 179
Default

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.

__________________
'67 Piper Cherokee
'66 Lemans
  #7  
Old 05-14-2025, 08:15 AM
pngoat pngoat is offline
Senior Member
 
Join Date: Dec 2005
Location: Madison, Wisconsin
Posts: 171
Default

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.

The Following 2 Users Say Thank You to pngoat For This Useful Post:
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:05 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017