I bought a 1994 last year as a project and am just starting to really mess with it. To get it drivable I just installed an new Opti and water pump. But the thing thats giving me the most trouble is the brake lights. I did some searching and reading, got under the dash and found a wire broke from the clip at the base of the column. I got it back in and thank god! brake lights worked. Moved the car around the yard a few times. Went to town and back. Worked fine. Tonight I got in it and hit the brakes to test it, worked once, then didnt work, worked again a few times, then quit completely. Got under the dash and the wire is still in the clip. Fuses are good. I took the brake light switch out and took it apart. Looked fine, cleaned it anyway. Nothing. Somebody point me in the direction of something else to check. I'm starting to hate this car....and I love C4s.

 

I also just checked and realized that my turn signals and hazards are not working.

 

Brake, stop, turn and hazard all pass through the turn-signal switch for lamps. You'll need to take your diagnostics further. Start again with the stop-light switch and you need to understand there's two similar switches at the brake pedal, a cruise release and the stop-light switch. A stop-light switch is very inexpensive, since you took yours apart and it's the last thing you've done I'd maybe start with a new one. Diagnostics should be very straight forward.

 

If only they made a device that could detect the presence of electricity, you could just use that to figure out where the electricity is, and where it quits being where it is supposed to be, so, like if it was on both sides of the supply fuse and went into one side of a closed switch but didn't come out the other side, then you could easily conclude that the switch is clogged up. Sometimes these clogs are so bad that the accumulated electricity creats so much heat and pressure that all the smoke leaks out. Smoke is the life blood of ALL electrical devices and once it leaks out, the device is kaput.

 

That device would be a test light or an multi - meter
Just ground it and probe the wire you get a reading or it lights up if 12 volts are present. Electrical issues are not clogs they are either open or closed, there is no smoke that leaks out, a switch can short and no longer work mostly caused by a faulty contacts in the switch itself or ground issues.

 

Bazinga. There *IS* smoke, and it usually smells like ozone.

If a switch "Shorts", by definition it passes current even when it is not supposed to do so, and the smoke remains in its containment vessel. If a switch, wire or other component loses continuity and it can no longer pass current from the supply (battery+ terminal) to the ground point (battery- terminal), then it is referred to as being "open". The development of this open state is triggered by the release of device smoke from the containment vessel. Similar to a tree falling in the forest, the smoke release occurs even if no one is there to witness the event.

 

Brake, turn and hazard lights work off of power that flows into the turn/hazard switch from 3 separate switched sources. The first source flows from a fuse that is always hot and supplys the brake light switch. When the turn and hazard functions are off and the brake light switch is closed, current flows directly through the turn/hazard switch and on to the brake light filaments of both brake lights.

The second source flows through a fuse that is only "hot" when the ignition switch is on. This source flows through the turn signal flasher and onward to the turn/hazard switch. When you actuate the turn signal function, current from the flasher is routed to the appropriate bulbs (front and rear, left or right). The circuit for the selected side is simultaneously removed from the supply line from the brake light switch and remains connected to the unselected side. That allows the unselected brake light to burn solid if the brake is depressed, and the selected side to continle flashing.

The third source coming into the hazard switch comes from a fuse that is always hot and passes through the hazard flasher and on into the turn/hazard switch. When the hazard switch is engaged, power from this source is routed to all four turn/brake filaments. To keep the switch design simple (and therefore cheaper and more dependable) the hazard portion of the switch does not isolate the power source coming from the brake light switch. That is why pressing the brake pedal with the hazards on makes all four lamps shine solid.

It's too bad the manufacturers don't print big thick books containing repair and troubleshooting information. You could just buy one, troubleshoot and fix your car and quit hating it. In fact, if there was a place on the internet where people advertised stuff they wanted to trade for money, you could go there and search and just maybe find such a book. In an ideal world, such a place would not allow the sale of any books with the words Haynes or Chiltons on the cover.

Bottom line, if all three functions are not working, I'd start by checking for the presence of voltage at the brake switch and both flashers. If power is absent from all three I'd look for problems at a common power source, such as a fuseable link. If power is present, I'd suspect a problem internal to the flash/hazard switch. All kidding aside, having a Factory Service Manual simplifies the troubleshooting process enormously, especially if the car is a "Project" with multiple problems to chase.

 

 

The current to the third brake light does not pass through the turn signal switch. So if it alone lights, then the problem is probably the turn signal switch. The wires through the column are part of the switch assembly. Years of tilting the steering wheel up and down can chafe the wires.