'67 Electra taillight issue

Hi guys, recently while driving my Electra, I notice the brake light goes out while my rear turn blinker is on. Happens on both sides. Turns signals work fine otherwise as do the hazard flashers and reg brake lights.

I wasn't sure if this is a fuse issue or something else. Any input is appreciated.

 

Hmmmm - just a guess - blinker and brakes use the same filament in the bulb. When you say it goes out when the blinker is working - the brake light on the other side is still on?
Is this something new?

 

That's the way it was designed from the factory: the brake lights bulbs are the same bulbs as your indicators.
So when you indicate, the turning signal overrules the brake lights on the side you are turning.

Also, when you put on your hazard lights and push the brake pedal, the hazards stop working.

 

I apologize, I messed up the actual situation. The brake lights work fine and the running lights are fine as well. The issue is, when I have my blinker on and hit the brakes, the blinker goes out. Neither the brake light or blinker show on that side. The other side will show the brake lights. This just started last week. Normally, the blinker stays on whether the brakes are being used or not.

 

Swap the indicator flasher with the flasher for the hazard lights and check if the problem is still there. If it's fixed after that, buy a new flasher.

 

So the problem I have now has actually changed. When the headlights are on, the blinkers and brake lights work fine. When the headlights are off, the brake lights work fine. When I use a blinker, the opposite brake light goes off. The blinker stays on though.

 

Are you saying when you turn on the RIGHT SIDE TURN SIGNAL that the LEFT side brake light goes out ??

It sounds to me like you have a bad ground somewhere and your lights are seeking a ground thru the tail lights or brake light

 

As said above, you probably have a bad ground. With a meter you should show less than 2 or 3 ohms resistance. If it is higher, cleaning the ground and redoing it is called for. I actually had to clean my fuse panel because oxidation had caused, well, wierd problems is all I could say
Just my 2 cents worth. (Probably more than it's worth. )

 

Are you saying when you turn on the RIGHT SIDE TURN SIGNAL that the LEFT side brake light goes out

That is correct.

I think it is a bad brake light relay, but I would think a bad ground would not come and go. I also can't find a fuse block diagram for my year. I have the Buick Service manual as well.

 

From the 1967 Buick Chassis Service Manual:

 

Thanks for this. Unfortunately, my fuse block does not have any lettering on it at all. Other than the round emergency flashers fuse, nothing is marked.

 

No such thing as Brake Light Relay . Brake lights go thru the Turn Signal Switch . That is why when you have the turn signal on for the right side the Left side stays on as long as you have your foot on the brake and the right side flashes .

YES . A bad ground will sometimes come and go . . The fact that you have problems when you turn the headlights on leads me to believe you have a bad ground and it is grounding thru your parking light circuit .

First check ALL your bulbs and make sure they are in the sockets correctly and are the right # bulbs . Then ground the brass base of the bulbs to a good body ground . See if that makes a difference .

The fact that its a 67 and the front parking lights do not light with the headlights says it is using that as a ground .

 

Lou, thanks for your response. The only time I have issues is when my headlights are off. When they are on, everything works as it should.

I know I have the correct bulbs in, because it worked fine for years and only started not lighting last week. I will check the connections at the bulb as well as the fuse panel.

 

https://www.teambuick.com/reference/years/67/67_lesabre_wildcat_electra_wiring.php

 

Thanks for the diagrams. I have been traveling for work, so I haven't had a chance yet. I'll post once I have more info

 

I have had great luck with taking the original wiring diagrams to a Fed - Ex Office and had them ENLARGE the original to a readable size . Just recently I had an 8.5 X 11 inch wiring diagram enlarged to 18 X 24 inches . Much easier to read . 2 copies cost me $5 .

 

That's a great idea.

 

I'm sure Staples and stores like it can do the same

 

Get Todd's - its already big! He sells a poster size.

 

Not for a YAMAHA XS 850 SG I'm working on .