Tail lights are always on - 1969 Camaro

[Dave69x33]

DaveK,

Yes, tried different flasher units to verify the one in the car was okay. No change to the issue.

Camaronut, 

It may come to that.  This evening I’ll confirm if it’s the tail or stop lights that are on.  If I pull a bulb socket and one filament in the bulb is on, that’s the tail light but if both filaments are on, that would be the brake lights, correct?

I also plan to swap and test the light and ignition switches one at a time to see if one got damaged. Both switches have battery power sent to them 100% of the time, correct?

If one of those two switches got damage with a bent spade pin or loose wire, I am assuming one of these switches could be the power source turning on the tail lights. Or is this a wrong assumption?

[camaronut]

I would defiantly check the wiring to the headlamp switch. - Now make sure you have that switch grounded correctly. There's a wire connected to that plate that goes in front of the headlamp switch - check that to make sure its grounded.  Dangit - I should have told you that in the first place.

[Dave69x33]

Camaronut…not worries! I really appreciate your input!!

When I pulled the headlight switch to work on the RS vacuum hoses, I did check that the ground strap was still in good shape. The ground strap may not be making tight contact with the face of the headlight switch when the special nut is is tightened to hold the switch in place.

[camaronut]

Maybe pull the headlamp switch back out - and make sure you have that connector in correctly.  - Make sure that the front of the headlamp switch is clean and the ground plate.  Also - make sure the nut is tight when you button it all up.  Check for anything that may be burnt.

[Dave69x33]

Will do.  Thanks again for all the input!

I’ll report back with what I find. Maybe it will help someone else in the future…bc this issue is very unusual.

Once I find the issue, I’ll listen to your other bit of advice…”leave well enough alone.” LoL!

[David K]

Now that there is more information,  I would pull the headlamp switch back out and then verify re-install is good.
Are the dash or courtesy lights on as well?
Marker lights in the front or nothing but the rear?

[MyRed67]

You mentioned that you removed the wiper motor.   I believe the wipers and the tail-lights run through the same fuse.   So I would start there.   My wipers recently stopped working.   During trouble-shooting I found I had power to all 5 terminals on the wiper motor as long as the key was in either on position.  I found out it was a ground problem at the switch.  It also could possibility of ground problem at light switch.

[Rick68]

Do the rear side marker lights come on when the taillights come on? I would think that they would be spliced together with the taillights. I think it's the brake lights that are coming on. If you disconnected the turn signal switch and the problem went away I would check the brake lights. The taillights don't go through the turn signal switch. You did have the  brake booster out so maybe the brake switch got out of adjustment when you reassembled it. Disconnect the brake switch and see if the rear lights come on

[Dave69x33]

Thanks for everyone's help! Problem solved! It was the brake light switch.

I double checked to verify it was the brake lights that were on. My bad early on thinking it was the taillights.  I changed the brake light switch, and it solved the problem.

I took the faulty brake light switch apart to evaluate the reason it failed. The switch is very simple with contact points separated by the spring-loaded plunger when the brake pedal is released. The points make contact when brake pedal is pressed, and the plunger extends out of the housing.  It’s still not clear why the switch failed. I do not see any internal damage to the switch.   The switch was a NAPA Echlin #SL169. I typically get good reliability from Echlin electrical parts. However, I had replaced the switch back in March 2022, so it did not have much usage between then and this new switch.

The switch looks like it was designed to have (2) sets of contacts 180 degrees apart. No broken contacts fell out of the switch when I took it apart.  Something in the switch failed to allow it to make electrical contact 100% of the time regardless of the position of the brake pedal.

Over the years I have had brake light switches fail where the brake lights would NOT turn on because the switch plunger stuck and would not extend when the pedal was pressed.  This issue was the opposite and the first time where the brake lights remained on regardless of the brake pedal position and the On or Off position of the headlight switch.  S I struggled troubleshooting this issue.

I can now rest again at night…lol.
Here are general pics of the switch.
Dave

[Dave69x33]

Here are views of the switch contact points in the open and closed positions.

[169INDY]

Wonder "IF" the Delco equivalent would be of any better quality and available.

[camaronut]

Awesome!!!!!  But nothing is as good as NOS GM parts.  I’d use this as a temporary fix and find the real deal.  Just my 2 cents.  I’ve found that AMC used lots of GM parts and marked them as AMC.  I’ve found a few parts like that and paid 1/4 the price….. but don’t tell anyone.  Lol