rear turn signals work but break lights don't (1 Viewer)

[MeanGene25]

i have a late '71 or early '72.

brake light and turn signal in one light housing per side (no yellow).

the turn signals work just fine but the brake lights do not light up.

headlamps, front turn signals, and rear side running lights are also just fine.

any suggestions or recommendations are appreciated.

 

[1962fj40]

I recommend fixing the brake lights..
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Check the usual things....bulbs, ground connection and and brake switch. Also look the the light sockets. They are prone to corrosion.


Robert

 

[charliemeyer007]

Get one of those test light probes and check if you got power to the socket - a VOM will also work. Your wiring diagram will be very helpful. Power to the other side means the brake light switch is working to me.

 

[Living in the Past]

There is a wire from the brake light switch into the turn signal switch. 72 believe has a plug versus individual wires. Pull the plug for the turn signal switch. Figure which wire is coming from brake switch and verify it showing 12 volts when the brake pedal is pushed down. If it has 12 volts problem in the switch.

 

[Paul_A]

One working and one not could be a bad ground or a bad bulb, but both out makes me think circuit. Check to be sure the switch on the pedal is making contact.

 

[Living in the Past]

One working and one not could be a bad ground or a bad bulb, but both out makes me think circuit. Check to be sure the switch on the pedal is making contact.

Brake and turn signal share the same element in the lamp. The brake light switch circuit runs thru the turn signal switch so it can interrupt the brake light signal on the side the turn signal in turned on.

 

[RodrigzCrzr]

If you wiggle the turn signal stalk they may come on. The brake lights go through the turn signals. This happens on my 71 as well. Bad contacts on my turn signal switch. Need to buy a new one.

 

[45Dougal]

Doesn't the brake use a different fuse to the turn signal on this setup?
Check your fuses first?

 

[3_puppies]

Doesn't the brake use a different fuse to the turn signal on this setup?
Check your fuses first?

after fuse check in and out of the brake switch up under the dash, make sure you have power to the switch and then out of it going to the turn signal switch

 

[RiverCityDave]

Ground. Bet it's the ground. It's always the ground.

 

[45Dougal]

Ground. Bet it's the ground. It's always the ground.

Except that the turn signal work.

 

[6f40j9]

Mine gave me fits until I changed the bulbs, switch, grounds…
I recently got my license plate light to work by cleaning the threads at the tailgate hinge (ground).
These are finicky things for being so simple.

 

[6f40j9]

Coolerman's Electrical Schematic and FSM File Retrieval

 

[RiverCityDave]

Except that the turn signal work.

Right, but the brake light switch works on these years by interrupting the ground, does it not? That occurs separately from the flasher for the turn signals, which interrupts the positive. I could be totally wrong here, and these changed some years, I think.

 

[Living in the Past]

Ground. Bet it's the ground. It's always the ground.

Right, but the brake light switch works on these years by interrupting the ground, does it not? That occurs separately from the flasher for the turn signals, which interrupts the positive. I could be totally wrong here, and these changed some years, I think.

The brake light switch sends twelve volts positive to the turn signal switch. The element in the lamp give a twelve volts positive from the turn signal switch. Same element in the lamp for brake and turn signal. Ground is provided thru the tail light housing. Bad ground would effect both brake and turn signal the same way.

 

[90WT]

@MeanGene25 Do your hazard lights work correctly? I recently had the same brake light issue. And also, my hazard lights weren't working. The fix for me was removing the hazard switch and cleaning contacts, as well as replacing the hazard switch fuse. Brake lights are tied into turn signal switch and hazard switch.

 

[Coolerman]

On a 1971-1973 the brake signal from the brake switch does NOT go through any Hazard switch contacts. It only goes through the turn signal switch.
I agree that the issue will be found in the turn switch. These are easy to take apart, clean and re-lube.

Note the Brown/Orange jumper wire is what allows the brake signal to go to BOTH rear lights.

 

[Slapshot]

i have a late '71 or early '72.

brake light and turn signal in one light housing per side (no yellow).

the turn signals work just fine but the brake lights do not light up.

headlamps, front turn signals, and rear side running lights are also just fine.

any suggestions or recommendations are appreciated.

Wondering if you ever found the issue? I’m having the same problem

 

[MeanGene25]

i checked the grounds and replaced the fuses.
the brakes lights lit up and things looked good.
but now, the fuse keeps breaking and i have not had the time to go further.

 

[wolfbak]

I chased down some gremlins after my full resto project on a '76. Here are a couple oddball things to try.

When I bought new OEM taillight assemblies, the bulbs were a slightly different spec. They were good bulbs, but they didn't light up! I changed them out, and all worked fine. It was like 1156's vs. 1157's. Check your specs. I was shocked that the system is so finicky!

The other thing I had happen was a fuse kept blowing and I would lose my horn, brake lights, and hazard light functionality. This one took a long time to figure out checking horns, grounds, voltages, and wiring! The problem ended up being my hazard light switch. All lights go through that switch, and even though the switch looked great externally, there was some corrosion inside. I had to disassemble the switch by cutting the clear insulating sleave, and prying the metal tabs open. Once inside, the green corrosion was obvious. I cleaned everything and reassembled with dielectric grease. Never had a problem since.

Good luck!