turn signal on brake lights go off
 

when I am braking and then activate the turn signals both of my brakes lights will cancel off.
If I do not bring the turn signal lever all the way to where it clicks into the cancel cam and the signals are activated it will not shut off the brake lights.
When I move the turn signal arm all the way to where the cam will have to shut off the signals is when I have this issue. Not sure whats up. All the wiring looks good and appears to be o.k., nothing appears spliced or anything.
I tried another cancel cam wiring harness (used one) but no luck. Any ideas? Hopefully something really simple I am just missing.

Change out your high low beam switch on the floor.. Its connected to everything your talking about and when it fails.. It does lots of weird things....

That just should not be. Headlight circuit is completely separate from turn signal circuits originally.

Is this on a 67? Sounds like you need a new turn signal switch. It controls what the brake lights do in the rear.

Charles

I doubt if the hi/low beam switch has anything to do with the brake/turn.

Interactions between the directionals and brake lighting are usually caused by the turn signal switch. Bad grounds at the rear or front lamps also cause funny things. Check your grounds first.

Do the signals work correctly front and rear without the brakes on? Do the brake lights work correctly without using the signals? Do the hazards work correctly?


George

yes this is on a '67 GTO.
The signals work fine when with headlights on or off, the brake lights work fine with lights on or off. All grounds appear good and I actually have a replacement trunk harness installed (had this same problem prior to installing the trunk harness).

I just hate to buy parts and start installing without actually diagnosing first.

The only time the signal/brake light problem is at issue is when the turn signal lever is all the way in position but if I hold it slightly where the signals activate but do not click the signal arm all the way this problem does not happen and I have brake and signals working just fine.

My vote is a signal switch going bad.

Charles

Does it happen with both sides for turn signals, or just one side?

I just hate to buy parts and start installing without actually diagnosing first

I would like to know what happens with the 4 ways turned on and you step on the brake.
The brake lights should over ride the 4 ways.
If they don't then i would also vote signal switch defective.

I'll continue with diagnosis and try a couple of items suggested here. If no luck will likely invest in a signal switch.

I have this same issue. What did you end up figuring out?

I would vote the turn signal switch as it happened on my 69 a long time ago . But mine the tail lamps would go out to.

Did you ever figure it out?

Turn signal switch is bad, or may need cleaning. I think 1967 was the first year for lane change turn signals. The turn indicator could be moved and the turn signals will work without going all the way to the "click". If the lights work in the "lane change" mode but not the "full turn signal mode", then it has to be the switch.

Yep. I replaced the switch. All is well now. Not a very fun job.