This problem started happening today all of a sudden out of nowhere. My brother told me my tail lights are on, so I figured I left the lights on. but nope, tail lights are on all by themselves.

The brake switch was replaced by me 2 1/2 years ago, and the rubber grommet under the clutch pedal is still there. Pressing in the brake switch button does nothing, and pressing the brake pedal down also does nothing, they don't get brighter or anything, they stay the same brightness.

I have made no changes to brake wiring at all. The only 1 thing is I had the tail lights modified beginning of this year to convert them to 99 spec, but I didnt cut anything, I simply unplugged them, and when the modification was complete, I plugged it back in.


Does ANYBODY know where I should start with this? im so pissed right now...

 

TNS relay stuck?

 

i would concur it may be the TNS relay under the hood

 

is the TNS relay the 60 amp relay under the hood? because I pulled that one out, and the brake lights turned off, but how would I know for sure if its bad, is there a way to check? wow what a way to spend christmas with the horseshit

 

One more thing to check before concluding that the relay is bad: The switch could possibly stick on internally (although this is not very common) and cause the brake lights to stay on.

So, disconnect a wire from the switch and see if the lights go out. If they do, it's the switch, not the relay.

 

I disconnected the brake switch, and the brake lights are still on, and not the tail lights but I mean the brake lights, as in it looks like someone is constantly pressing the brakes. If I pull the 60 amp TNS relay however, the brake lights do go off, but im not sure if that would conclude that its bad.

Should I replace that relay and go from there? ha funny... looks like I fixed that coolant leak finally from my other thread, and the same day I fix it, this happens

 

The TNS relay shouldn't be 60 amp - that's like the main relay for most of the electrical systems on the car. I THINK the relay for the lights is in the relay box that's up front by the hood latch under the stock airbox duct.

If it's not a bad relay, it could be a problem with aftermarket wiring, like with a stereo, gauges, etc.

Dale

 

Sounds like you pulled a fuse instead of relay.

 

Ok I found the actual TNS relay itself, and pulled it out, and the brake lights are still on. I called up Ray at Malloy Mazda, and he said the way to check to see if the relay is bad, is to swap out both the blue relays next to each other, because they are interchangeable, and if the brake lights go out when I put the other blue relay in, then its the relay that is sticking closed.

Well I tried that, and it made no difference, so the TNS relay is fine, brake switch is good, and the rubber grommet for the brake pedal is still in there.



I do have an aftermarket stereo system with new wiring, and an aftermarket head unit, but Iv'e had those in there for years, and made no recent changes to anything, so the chances of that being the problem are highly unlikely.

The ONLY thing I will mention, is that I was resealing a pipe plug on the thermostat housing about 2-3 days prior to the brake light issue.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/coolant-level-low-no-visible-leaks-865339/

Based on everything I stated above, doesnt anybody know if it would be a short to ground somewhere in the wiring harness? because I always thought a short to ground would blow the fuse, which in my case this obviously did not happen

 

Problem solved!!!

 

well what was it?

 

It wasnt the TNS relay, and it wasn't the Stop light switch. It was a short to power.

I used this wiring diagram to diagnose the problem. When I pulled the 20amp STOP fuse, the brake lights turned off, verifying that all the wiring under the hood up until that 20amp fuse is good. Next, I pulled off the connector for the brake light switch, but the brake lights did NOT go out, meaning there is no power going through the switch. If there WAS power going through there, then pulling the connector apart would turn off the brake lights, because it would break the circuit, but that did not happen.

Because disconnecting the switch did not turn off the brake lights, I then verified all of the wiring from the brake light switch to the actual tail lights themselves to be good. So I knew the problem would lie between the 20 amp STOP fuse and the brake light switch.

We all know electricity always finds the shortest path to ground, and the switch is considered a load. It turns out that the "green/white" wire, and the "green" wire shown in the picture were indeed wrapped around each other touching bare wires. Therefore the easiest way to get to the tail lights, would be to bypass the brake light switch altogether, and go straight from one wire to the next, all the way to the brake lights.

Im bad at explaining things I hope that made sense thanks guys for all the help!

 

it does. thanks!