boblozito

Hi all and thank you in advance for any assistance. I have a 1966 Coupe and the brake lights are not working. I have checked the fuse, lights and replaced the switch but not working.

Are there any inline fuses perhaps lurking someplace that would account for the problem? All other related lights are working fine; driving lights, turn signals, etc. I was able to bump the switch with a wrench and the brake lights came on but have since stopped working. Appreciate any suggestions before tearing things apart.

66jack

Check the grounds...each light back there has its own ground...even the license plate light..

65GGvert

A bad ground won't cause that. The tail lights and brake lights use the same bulbs, grounds, filaments, and wires exactly. Only two possibilities, and you changed the brake liht switch.. Your problem is either at the brake light switch or turn signal switch. Any time the battery is connected, key on or key off you should have 12v on the orange wire (or black with orange stripe on some cars), when you press the brake pedal down, the plunger extends down and makes contact with the white wire on the brake light switch (or black with white stripe on some cars). That white wire then goes through a connector on the steering column and to the turn signal switch.
If your courtesy lights and dome light (on coupe) are working, you have voltage out of the fuse box and on the orange wire. If they are not working, you don't have the voltage out of the fuse box.
If "bumping" the switch made them come on, I would check the white wire where it goes into the connector on the steering column above the brake pedal Sometimes your foot can get up in there and push the white wire out of the connector. Make sure it's fully inserted into the slot on both sides of the connector. Make sure the plunger on the brake light switch is fully extending when you press the brake. Again, the "bumping" making the brake lights work sound like you have a loose wire or bad connector on the brake light switch itself. You can CAREFULLY short the orange and white wires on the brake light switch together and see if the brake lights come on and that will eliminate the turn signal switch and fuse box as possibilities and your problem is at or in the brake light switch. If everything is good all the way through the white wire at that steering column connector, you have a bad connection in the turn signal connector where the white wire connects.
Use this order:
Are your courtesy and dome lights working when you open the door or rotate the dash light dimmer all the way counterclockwise? If they are, skip the fuse box and go to the white wire on the brake light switch and make sure it's connected to the plug.
Look at the white wire going from there up to the turn signal switch. The connector is attached to the steering column under the dash and has several wires. The only one that can cause your issue is the white one. You can confirm the voltages with a test light or volt meter. If you have voltage on the output side of that connector on the steering column when you step on the brake, you have a turn signal connection issue. Post back after you check the above, because the turn signal switch won't be as easy a fix as these other possibilities.

PinkVetteLady

Most likely the turn signal switch..

65GGvert

Based on what? Do you know something about the car that he didn’t tell us?

65GGvert

One other thing I forgot to ask. Have someone hold down on the brakes with the key off and turn the turn signal back-and-forth from left right left right left right and watch from the rear to see if you get any flicker or if the brake lights start to work. If they do, then you most likely have a bad turn signal switch. Again, do it with key off. You can work out a way with a mirror or a garage door in the dark, but having someone help you is the easiest.

Tom Austin

Sounds like the turn signal switch to me! If you need one . . . this one works well!

https://www.ebay.com/itm/16275832013...IAAOSwnNBXaYVg

Tom

R66

R66 had and intermittent brake light problem. The radio capacitor flag terminal was hanging loose as it had been removed. The female terminal in the connector had been spread when the flag connector was installed due to the additional thickness of the flag. Thus the female terminal would make contact with the male terminal on the switch only once in a while when the moon was right.
It as difficult to find, because the VOM reported 12vdc voltage at the back of the connector when I tested it.
Wiggle the connector while depressing the brake pedal and see if the brakes come on. You can also remove the connector and use a jumper between the two contacts and should get brake lights if this is the problem.
Just a possibility.
Ron

65GGvert

Anyone who changes a turn signal switch without checking the easier stuff first deserves what they get.

boblozito

Many thanks to all who replied with their advice/suggestions. 65GGvert hit the bullseye with his suggestion to trace the white wire back to the two-piece harness that is mounted on the steering column. The white wire had been partially dislodged from the harness and was not making contact with the white wire on the opposite piece of the harness. Special thanks to you Jack in Charlotte. Hope to make my way there for the QCCC event this year.

The collective knowledge on this website is nothing short of amazing. So many folks with vast knowledge willing to share that knowledge with those in need.

leif.anderson93

When it comes to electrical gremlins on these old plastic cars, there is no better diagnostician than Jack (65GGvert). If one is smart, when he speaks you listen...I know I do.

berlinlake

For what it's worth, when my brake lights weren't working a couple years ago it was also the wire harness connector mounted to the steering column under the dash.

Definitely worth checking before tearing into anything else.