1 brake light out....turn signal switch?

[Kllrbee]

Hey all,
69 Dart. Noticed got one brake light out. Swapped sides and the bulb is good. Taillights and turn signals work (hazards dont). But the signals are getting a little twitchy sometimes. Going fast or intermittent.
Its been awhile, but I thought I remembered that the brake signal goes thru the TS switch before going down the line to the 1157s. And if the TS switch is on its way out, it could "disrupt" the brake signal. I know my lingo sux here, but Im not an electrician by any means. Im hoping you guys know what Im referring to and can verify if thats the case. If so, Ill go grab a new TS switch to see if that does the trick.
Also, could that also be why the hazards dont work? I thought they are on their own switch....but figured I should ask as long as were at it.
Thanks fellas!

 

[67Dart273]

If you are CERTAIN the signals work normally, it is the switch. The TS switch indeed steers the brake light switch voltage depending on which signal is energized, AKA with no signal, the TS switch sends brake switch power to both left and right signal filaments. With the left TS selected, the switch continues to route brake power to the right filament, but interrupts brake power to the left, and instead, connects the flasher to the left filament.

 

[413]

Hazards have a separate flasher From the turn signals.

You need power to the bulb and ground to the taillight bucket for bulbs to light up.

Does the turn signal work on the same side as the brake lamp won’t light? They use the same wiring and filament in the bulb.

 

[Kllrbee]

Thanks. Yes, both signals work and as 67dart273 described. When I use the left TS and press the brake, the right brake lights up and vice versa. Whichever is the last brake light to light up is the one that works when pressing the brake only with no TS selected. Although, they both worked the last time so I left it for the night....LOL Good to end the night on a positive note.
Gotta be the TS switch. Thanks guys.

 

[Inertia]

If/when you get new switch, plug it in and check it, before you install it, to make sure it works, and to double check your diagnostic.

 

[toolmanmike]

Most light issues on these old cars are bad grounds. I had a front turn signal that was giving me fits and I soldered a 14 g. wire to the socket and grounded it to the body. Fixed.