Help, Electeical problem?

[Simok]

Originally Posted by RZNT4R

That splice on the pink is making me want to puke, that's why I'll never trust "installers".

I also *just* noticed you said you had a 4th brake light mod... and you've got funky stuff going on with the brake switch. I don't know how it was wired, but if it was wired directly to the brake switch with more than one wire, I know it's been done wrong, disconnect it.



Adding a 4th brake light should be two wires: One 12v on the brake light wire and one ground in the back of the car.

Its a 4th brake light/taillight. 3 wires red, black, and green wired in right behind the bulb to their respective colors, all connections are solid.

Originally Posted by 1GiantTurtle

you might have something wrong with your brake light switch, but first always check the EZ stuff go under the drive side footwell area and pull out the "STOP" 7.5A fuse and check it

Fuse looks good.

I checked everyrhing out again, this time disconnected the hu includng the purple wire. Taped the pink one where the bare coper was showing. I checked all other wiring as best I could and found two possible issues.

1. There is a wire leading to the clock/hvac it has 3 wires in black insulation, the insulation was pulled back exposing 3 conductors. I taped this back up. Was unable to get a pic or see very well as I didnt take the whole hvac unit out.

2. There was a brownish wire on top of the pink wire under the hood release pannel that had a tiny nick it the insulation where I could see copper. I taped this up.



I drove the car about 20miles trac control is working as it should. No warning lights. And clock is functioning normally. This is basically what happened last time then a few days later it all came back. So well see what happens later this week

[RZNT4R]

That third brake light is probably led, you could have a busted diode and current feeding back from the parking lamp circuit through the 4th light and back up the brake lamp circuit.

[Simok]

Originally Posted by RZNT4R

That third brake light is probably led, you could have a busted diode and current feeding back from the parking lamp circuit through the 4th light and back up the brake lamp circuit.

It has a normal dual filament bulb, just like a normal brake like would have. I can snap a pic of the bulb if that helps.

[RZNT4R]

In that case, check the resistance on the ground splice.

The C1249 you're getting is

Any of the following is detected:

The vehicle speed is 10 km/h (6 mph) or more, the accelerator pedal is depressed, and the stop light switch is on for 60 seconds or more.
When the stop light switch is off, the master cylinder pressure is increased.

I wouldn't have been surprised to see a dubious LED bulb fail, but it's also possible with a filament bulb if there is resistance on the ground. With the parking lamps on some voltage will go the other way, through the brake lamp filament and back up towards the brake switch/VSC ECU. If you don't have one already, go get a cheap DVOM to check the resistance, and while you're at it, check the voltage on the brake circuit when you turn on the park lamps.



BTW, those vampire splices on your rear tail light are a terrible way to install something, they can cut filaments and even in the best of cases, only make partial contact with the wire. In applications where you've got an actual electrical load (like an incandescent bulb), you're just asking for something to fail. Have a look at the bulb also, I've seen bulbs failures where the a filament broke and contacted the other mid-way across it's span and got welded.

[Simok]

Originally Posted by RZNT4R

In that case, check the resistance on the ground splice.

The C1249 you're getting is



I wouldn't have been surprised to see a dubious LED bulb fail, but it's also possible with a filament bulb if there is resistance on the ground. With the parking lamps on some voltage will go the other way, through the brake lamp filament and back up towards the brake switch/VSC ECU. If you don't have one already, go get a cheap DVOM to check the resistance, and while you're at it, check the voltage on the brake circuit when you turn on the park lamps.



BTW, those vampire splices on your rear tail light are a terrible way to install something, they can cut filaments and even in the best of cases, only make partial contact with the wire. In applications where you've got an actual electrical load (like an incandescent bulb), you're just asking for something to fail. Have a look at the bulb also, I've seen bulbs failures where the a filament broke and contacted the other mid-way across it's span and got welded.

Which point should I be checking all that at? Correct me if Im wrong but wouldnt opening those clips be a bad idea as the wire will be cut in half? How should I have spliced them together? Tape and twisting didnt see very permenant and the kit came with those clips.

[NCtoBRZ]

Originally Posted by Simok

Which point should I be checking all that at? Correct me if Im wrong but wouldnt opening those clips be a bad idea as the wire will be cut in half? How should I have spliced them together? Tape and twisting didnt see very permenant and the kit came with those clips.

Taps are notoriously unreliable. I used them on a previous car for a backup camera installation and after a few months the camera would sometimes work and sometimes not. I removed the taps and soldered the wires and never had a problem after that. The wires should not be cut in half after removing the taps, they are only designed to nick the edge of the wire... which is why they tend to make such a poor connection to begin with. So to answer your question, get rid of the taps and solder the wires, then heat shrink or at least e-tape over the solder.

[RZNT4R]

Originally Posted by Simok

Which point should I be checking all that at? Correct me if Im wrong but wouldnt opening those clips be a bad idea as the wire will be cut in half? How should I have spliced them together? Tape and twisting didnt see very permenant and the kit came with those clips.

At which point? Whenever.

Those splices have a removable connector going to the 4th light, so even if you don't feel like doing instrumented tests, it's easy to just disconnect it and take it completely out of the equation while you continue to use the car normally.

[Simok]

So I have completely disconnected the hu and taped the two exposed wires I found. So after driving it for a week, about 100 miles no issues. I havent messed with the 4th brake light yet, in order to narrow down the issue.


My next plan is to recconect the head unit as it was instaled to see if the problem was coming from one of those exposed wires. Especially since one was very close to the purple splice, which also had bare coper showing. If this solves the problem, I will then solder that purple splice and hope thats the end of it. Once it is fixed I will then solder the 4th brake light.

Since the dealer ran the codes Im not sure what they used. Will they show up with a normal obd ii reader, or is it a special code reader? I did a normal obdii diagnostic and no codes.

Dose this sound like the correct way to go about this? Anyone have any other suggestions? Thanks for all the help so far.

[RZNT4R]

What scan tool did you use?

Most inexpensive generic scan tools will only scan the PCM for standard SAE "P" codes. If you want to scan the brake and traction systems "C" codes like you had you have to go one step up in the quality ladder.

[Simok]

Originally Posted by RZNT4R

What scan tool did you use?

Most inexpensive generic scan tools will only scan the PCM for standard SAE "P" codes. If you want to scan the brake and traction systems "C" codes like you had you have to go one step up in the quality ladder.

I used the one autozone gives you to borrow, not sure on the make/model

[humfrz]

Originally Posted by Simok

So I have completely disconnected the hu and taped the two exposed wires I found. So after driving it for a week, about 100 miles no issues. I havent messed with the 4th brake light yet, in order to narrow down the issue.


My next plan is to recconect the head unit as it was instaled to see if the problem was coming from one of those exposed wires. Especially since one was very close to the purple splice, which also had bare coper showing. If this solves the problem, I will then solder that purple splice and hope thats the end of it. Once it is fixed I will then solder the 4th brake light.

Since the dealer ran the codes Im not sure what they used. Will they show up with a normal obd ii reader, or is it a special code reader? I did a normal obdii diagnostic and no codes.

Dose this sound like the correct way to go about this? Anyone have any other suggestions? Thanks for all the help so far.

Sounds like a good plan to me.


humfrz

[RZNT4R]

Originally Posted by Simok

I used the one autozone gives you to borrow, not sure on the make/model

Well...

It's a sure thing that the dealer used something else, their scan tool is a laptop, a j2534 interface and techstream, giving full access to every computer on the car. I used that thing once, bloody powerful.

Now, you say It's autozone and they let you borrow it for free? It's probably that cheap blue thing at 59.99, which will only read engine P codes, not chassis C codes.

https://www.autozone.com/test-scan-a...92763026288834

[1GiantTurtle]

my friend just brought me his brz with the same issue his 4th brake/taillight shorted, hes running those Chinese 7443 LED bulbs u see all over ebay/amazon pull the bulb and car is all good and happy, it was feeding power to the brake "STOP"circuit causing the bcu to freak out, try pulling the bulb or disconnect the t-taps from the taillight