Brake Light Issue

Folks, I've got an issue with my brake lights and I'm running out of patience with the issue. I noticed a few weeks ago that my brake lights weren't working when I had my regular lights on. They work fine when I don't have my lights on, but when the lights are on are on nothing happens when I hit the brakes.
Then I also noticed that the same thing is true for the rear blinkers. They work fine when the lights are not on, but when they are on the driver side blinker works fine, but the passenger side doesn't.
Also, when the lights are on, the passenger side rear light is much brighter than the driver side (as if the passenger side brake light was constantly on).
I've changed out the rear light fixtures, tried to make sure they were making a good bond / connection with the body, changed the bulbs and also tried to make sure the wires were making good contact with the brake light switch. My brake light switch seems to be a pressure switch on the brake lines... not sure if that is authentic.

 

My first guess - Grounding issue is likely. Very common and confusing.

The turn (blinker) and brake bulb filaments are one and the same. A poor ground can cause weirdness like that filament seeking alternative ground through the running light filament/circuit, but that may be negated when the lights are switched on.

It also sounds as if one bulb socket may be wired backwards too, in respect to the light being brighter.

Anyway - I would check and clean all sockets, bulb bases, casing to body, etc etc etc, as a starting point.

 

Welcome from Michigan, check out the turn signal plugs by the heater, under the hood, they are bullet plugs and need to be unplugged and cleaned really well and plugged back in. The spartan turn signal gets corraded at the heater plugs and will not work, I had that problem and all it was is old age. I feel that way too.

 

X2 on grounds. I'd start there just to be sure.

 

x3 grounds.....will drive you nuts, clean up the tail light housing and tub where they bolt together

 

x4 yep check grounds at lights

 

You think that could still be the case even though I replaced the lights? I also cleaned and sanded the body where the light connects. For some reason I think you're probably right, but it's just hard for me to believe.

 

X5 for a ground.
Just because the light receptacle is grounded to the body, how can you be absolutely certain the body is 100% grounded to the battery. Connections corrode and rust. I once had a completely new taillight fixture not function correctly. Uh huh, the light bulb socket was not completely grounded to the housing.

 

Also, the terminals on the bulbs, and the inside faces of the sockets will reward careful cleaning.

 

This. Check your grounds all the way back to the battery. Are the ground straps for the chassis, engine, and body all clean and working well?

 

You guys are a wealth of information! I'll work on this stuff this Saturday and try to remember to report back in!

 

That is because the light wires are swapped at the tail light.

 

Well, Walt is the winner. The wires were crossed! I have no idea how or when that happened, because I know they worked at one time and then I have no memory of touching it.
I'm sure you guys have done this before, but I just spent hours and hours trying to fix a 5-minute problem. I wish I had tried the easiest thing first!
Thanks for your help!

 

Well, after cleaning up the garage now I realize I still have one more issue. My guess is this last thing has been happening all along I just didn't notice it since I was focused on the passenger side. On the driver side, when the lights are on and I hit the brake the light just goes off completely. What do you guys think that is? A bad wire or a bad switch maybe? I changed the bulb and the new and did the same thing.

 

Check the bulb socket real well, that is usually the problem, it is not grounded properly. The light is getting ground by back feeding through the wires, and when you add more positive to it, it fails. I have found that with rust around the socket here in the Rust Belt. Good Luck.

 

a 12 volt test light is your friend
you will know if it's a wire issue or light

 

This.