Only one brake light

[Charlie '64]

I was out for a top down drive last Sunday and a guy pulled up beside me and told me I had a tail light out. Bought a bulb and went home. It wasn't the bulb. My car has back up lights so we are talking the out board lamp on the passenger side. Drivers side everything works, tail light, turn signal and brake light. On the passenger side everything works except the brake light( tail light, turn signal and back up all work). To shorten this I traced the colored wire to the half moon shaped connector on the steering column. I checked the brake switch on the brake pedal and have power going in and coming out (when the brakes are applied). Now at he connector, I found the colored wire for the drivers side and have power (when brakes are applied) on both sides of that connector. I also found what I believe is the colored wire for the passenger side, but I have no power on either side of the connector when the brakes are applied. So, am I on the right track here? Do the right side and left side separate at the turn signal? Could this be wher my problem lies (turn signal switch?)? I'd appreciate some input before I pull the steering column. I didn't check the flasher, but thought if I don't have power at the connector, my problem probably wasn't the flasher. Thanks for the help!

 

[Vette66AirCoupe]

I had a similar problem on my '60 Corvette and found it to be caused by the turn signal switch being out of adjustment. The trun signal cancels the brake light out on the side which is flashing so that when you step on the brake with your turn signal on the signal continues to blink. On my '60, the switch was working well enough to turn off the turn signal but wasn't centering quite enough to allow the brake light to work. Try putting the turn signal on the side opposite the one that won't light when you apply the brake and then see if the brake light works. If it does, the problem is in your turn signal switch. Good luck.

 

[WayneC]

From the electrical diagram for my 63...

The harness connector on the turn signal switch on the lower steering column has slot connectors in a 3-2-1 row configuration.

On a 63 the 2-connector row feeds the rear turn signals, with a purple wire going to the driver side tail light and a violet (ie, light purple) going to the passenger side tail light.

I think the 1-connector "row" is a 12v wire that is turned on by the brake light switch to feed both the purple and violet wire connectors via the turn signal switch.

The outer connectors in the 3-connector row go to the front turn signals and to the dash turn signal indicator lights, so the dash indicator lights probably look normal despite malfunctioning rear turn signal lights; the center connector in that row is the pulsed 12v power feed coming from the turn signal blinker module at the fusebox, I think.

If you have power to both the purple and violet wires at the turn signal switch with the brake on, but with the brake lights off you see pulsing to the purple wire with the left turn signal on, but not to the violet wire with the right turn signal on, then the problem is likely in the turn signal (since the brake lights are both working).

There is a slider on the side of the turn signal switch that is moved by a stiff-wire cable (from the turn signal lever) that passes through 2 tabs, one on either side of the slider; the tabs "trap" the cable/wire by exerting pressure on it. The slider rides in a cut-out slot in the turn signal switch metal housing; when the turn signal lever is moved up, the slider moves to one end of the slot; when the lever is moved down, the slider moves to the opposite end of the slot. With the turn signal lever in the off (center) position, the slider should be centered on/in the slot. So begin by checking that slider for correct positioning while moving the turn signal lever to signal left and right turns, and adjust the cable wire in the tabs if needed. If the slider does seem to be positioning correctly in the slot in both directions, but the violet wire connector on the switch is not getting a pulsing 12v signal when the lever is in the right turn position (yet the right brake light is working) then it's likely the switch is the culprit.

You probably could test this also (without power): disconnect the harness from the turn signal switch, and use a multimeter to check continuity (ohms scale) between the center connector of the 3-connector row and each of the two connectors in the 2-connector row, with the turn signal lever in each of it's positions... I think you should have continuity to only one (or the other) of the two connectors with the slider at either end of it's travel.

 

[Charlie '64]

Terry and Wayne, thanks for the replies!! You have confirmed what Ibelieve, that the problem is probably in the turn signal switch. I'll try to get into the steering column between now and this weekend (if work cooperates) and let everyone know what I find. Also, in my tries to put the rear of my car back together, does anyone have an easy way to put the exhaust extensions back on the mufflers #$%^*!! Thanks again for the help, the knowledge on this forum really helps us amatures.

 

[Vette66AirCoupe]

Charlie,

I'd start a new thread with your exhaust extension quesstion. You'll get more readership that way.

 

[JohnZ]

The issue is definitely in your turn signal switch, although the '64 switch, function, wiring, and connector is completely different than the '63 (the '63 was a unique one-year-only remote switch design). The 20-ga. dark green wire coming out of the curved connector below the steering column goes to the passenger side "bright" filament (carries both turn signal and brake light current). Since the passenger side turn signal works but the brake light doesn't, there's a contact failure inside the switch.