Break light turns signal issue

[David68Newport]

Was driving the 68 Newport this morning and noticed when I hit the breaks my turn signals come on in the dash and the fender lamps. When I put the turn signals on both sides flash like hazard lights. Any help would be appreciated Thanks.

 

[Big_John]

That is one of two things. Either bad grounds at the tail lights (most likely and easiest to fix) or a bad turn signal switch.

My money is on bad grounds. Check by running a wire between a good ground and the tail light housings.

 

[David68Newport]

I'll give that a try thanks

 

[SPF Required]

In my 68 300 there is a spot in the trunk where all the tail light grounds come together. (My trunk is carpeted so it took a while for me to find) but if memory serves, it was on the driver’s side of the trunk. Getting that connection solid again helped a lot when I had similar problems on the back end of my car.

 

[David68Newport]

In my 68 300 there is a spot in the trunk where all the tail light grounds come together. (My trunk is carpeted so it took a while for me to find) but if memory serves, it was on the driver’s side of the trunk. Getting that connection solid again helped a lot when I had similar problems on the back end of my car.

Thanks for the info

 

[David68Newport]

That is one of two things. Either bad grounds at the tail lights (most likely and easiest to fix) or a bad turn signal switch.

My money is on bad grounds. Check by running a wire between a good ground and the tail light housings.

So am I looking at the electrical diagram right that the taillights are grounded to the housing itself? So any bulb could be giving me a ground fault?

 

[Big_John]

So am I looking at the electrical diagram right that the taillights are grounded to the housing itself? So any bulb could be giving me a ground fault?

Yes, the lights ground through the housing to the body.

"Ground fault" is the wrong term... Ground fault is when an energized circuit contacts ground and it's used in describing problems with AC (ie. house) wiring.

The metal base of the bulb is the ground. You could have a problem at the bulb, where the socket connects to the housing or even where the housing connects to the body.

 

[David68Newport]

Yes, the lights ground through the housing to the body.

"Ground fault" is the wrong term... Ground fault is when an energized circuit contacts ground and it's used in describing problems with AC (ie. house) wiring.

The metal base of the bulb is the ground. You could have a problem at the bulb, where the socket connects to the housing or even where the housing connects to the body.

Ok thanks John I'll give that a look. Chopping away at this when I have free time.

 

[rags]

I hit the breaks my turn signals come on in the dash and the fender lamps. When I put the turn signals on both sides flash like hazard lights.

had that exact problem in my '65. was the ground for the turn signal indicators in the instrument cluster!

 

[Badvert65]

My bet would be the turn signal switch. Front and rear turn signals are separate parallel circuits. There is a front turn signal circuit which includes the dash indicators, and a rear turn signal circuit that includes brake lights. If pressing on the brakes illuminates the dash indicators, there is a short between the front and rear circuits and the most likely place would be in the signal switch itself. 'In-town' driving, long periods with brakes on and turn signals activated can make the contacts in the switch get hot enough to melt into the nylon and shift around. Once this happens, you can see all sorts of weird symptoms. The switch contacts are nothing more than small rivets and brass loop crimps.
jus sayin....

 

[Badvert65]

I have had a bad ground in my dash that caused a strange problem. My dash signal indicators would be 'on' all the time and when I would activate my turn signals, the dash indicators would blink 'off'. Really strange what ground loops can do.