Turbotrad

My condition...

1969 Corvette coupe

None of the 4 tail lights come on when car is running.

Brake lights do not light up when pedal is pressed.

When headlights are turned on, headlights and all running lights come on to include the outer two tail lights. Remaining lights do not come on when brakes pressed in this configuration and operating outer two lights do not go double bright.

Applicable fuses not blown.


Any ideas?

cargo247

Ground 95% of the time.
Todd

Turbotrad

...so...where do I start my search? Where are the grounds located?

Young69Owner

I would also check the brake light switch. I believe they are capable of failing. Would both grounds go at the same time?

...Roger...

Take a length of wire and strip both ends,ground one end to the neg term of the battery, touch the other end to the bulb case. This will be a temporary ground and if the bulb lights you have a ground problem.

19LEW71

If it is a ground, its most likely to be at the light directly behind the driver side. It grounds on the frame and than loops light to light going towards the passenger side.

Turbotrad

Another part of the puzzle.

The inner lights light up when I shift to reverse. So the bulbs are good and all the lights CAN get power in certain configurations...

Turbotrad

Oh and one more thing I tested with a multimeter and I do have 12v power at the brake pedal switch.

It's really confusing. All the lights work, there's just some way the system is designed that power is not getting where it should in certain configurations. Very strange.

72LS1Vette

I've read the whole thread but this post has the best summary of your problems. I have not had all of my lights working correctly yet either, so I could be off-base, but I think you might not understand how some of the lights work.

When the headlights are off there will be no running lights or tail-lights lit. There were no daytime running lights in 1969.

The inner lights are just reverse lights. You indicated that they work so there isn't a problem there. I believe the red surrounds on those lights are just reflectors.

If the outer tail lights come on when the headlights are on the running lights are OK.

It looks like your only problem is the brake lights. You didn't mention if the directionals are working. Most of the tail light wiring runs through the directional switch so if you are having any problems with the switch that could be contributing to the problem.

My tail lights, brake lights and directionals used to work, but when I changed the steering column to one with a broken directional switch the lights stopped working correctly.



Rick B.

noonie

If anything in the rear works, then your ground is fine. BTW it is above the drivers muffler on the frame tail with the antenna ground.

1st check for voltage out of the brake lite switch, if needed these are available anywhere for less than 10 bucks and fit many GM installations including Chevettes.

2nd disconnect the harmonica plug on the lower steering column and clean. This is often the problem, as the contacts oxidize. There is another harness connector under the dash by the A pillar.

Next on the list is the directional switch.

If the rear signals and hazards work, then it is probably the brake switch.

Young69Owner

My '69 has Daytime Running Lights.

I am pretty sure that each brake light has a separate ground which is shared with the running light on that side-guys think about how an 1157 bulb works... Your problem is the power going to the bright setting. Please see if your directionals and hazards work and post back.

Turbotrad

First let me thank everyone for investing in this thread, I really appreciate it.

Hazards light up when switch is used.

Turn signals flash outer tail and front lights as they should.

Outer of four tail lights light up when headlights are on.

Backup (inner of four tail lights) light up as they should in reverse.

All side and front running lights come on when headlights switch is pulled.


So are you telling me that the only time under normal daytime conditions that the tail lights come on is when the brake pedal is pressed?

I thought otherwise for some reason. The contacts on the harness going to the brake switch have 12v of power.

noonie

Let's clarify the terminology.

You have tail lites and brake lites. The bulb has 2 filements a low watt (tail lite) and a higher watt (brake lite that is brighter). They can work independently or be on simultaniously (lites on at night and then applying the brakes). The brighter filement also acts as the turn signal or hazard signal. If either one works, the grounds are good since the bulb shares the same ground.
They both work in the outer lite assembles in the rear.
The inner lites are backup lites and the outer ring are reflectors only, they don't lite up.

From your first and last post, you indicate just your brakes lites are not working.
I assume you tested the orange wire that feeds the brake switch and got 12v.
Next, test the white wire also on the brake switch, with the brake pedal depressed and see if you have 12 volts.
If not, then the brake lite switch is bad.
If yes, then test the dark green and the yellow wires at the harmonica connector with the brake pedal depressed.
If no, then the turn signal switch is bad,
Everything else to the back of the car is good because the signals and hazards work.

72LS1Vette

Actually daytime runniing lights refer to headlights and not tail lights. They weren't approved for use in the U.S until 1995 so I am confused by what you are referring to as daytime running lights. If your tail lights come on when you start the car there is something wrong.



Rick B.

Young69Owner

Haha, Rick! No, I have put a DRL-1 module in my car. My amber lights come on bright when my running lights are off.

Mashman

I just had to replace mine - would sometimes work, the switch failed internally.

I think it cost a whopping $4 or something like that at AutoZone, and it's very easy to change, so it's worth a shot.

If not familiar with this switch - it's a plunger type switch that gets depressed when you press the brake pedal and turns on the brake lights.

Turbotrad

The problem was the brake switch. Just replaced it with the $4 Autozone part and the brake lights function again.

This is probably one of the few times with our cars where the most simple solution is the correct one. I'll enjoy the victory anyway.

Thanks for the help guys.

Brad

19stingray69

I'm hoping this is my problem also