Skar-ZA

Hi all.

Ive tried searching the web, using our local forums, as well as searching here. I have yet to find what i need. I own a 97 Honda civic B16a EK4, from South Africa.(no cruise control, has a 2 wire brake light plug for the switch). I also have the ctr conversion done to them, been working fine for over a year until now.

I was told by a friend recently that i had no brake lights as i was unaware(normal taillights still work though). I checked all the fuses with a multimeter, all have continuity. i then checked to voltage going into the plug that connects the brake light switch. it has continuity and 12v. i then checked the bulbs, both filaments have continuity as well. checked the bulb holders, ground and tail light contact has 12v. i decided to unplug the switch and use a bridge wire so essentially bypass the switch(i didnt have to use a brick or have some1 else press the pedal) so that while i investigate i could see if they came on. after doing this i checked the voltage from ground to brake light contact on the bulb holder and got a low value(in mV - indicating to me a break in the wire.) however checking for continuity and it beeped out. i then decided to remove the tail lights for better inspection(while the switch plug was bridged). i removed the right hand/driver side tail light first, checked the plug pins on the tail light, the beeped out as well. checked the strip connector i used for the conversion and that was fine too. then started removing the left side(passenger side light) while i wwas removing it, the brake light suddenly came on. i finished removing it and repeated the same scenario i had dont on the left, only this time i decided to use some Q20 on the plugs and strip connectors in case of any corrosion/moisture. i also checked the immediate wiring on the loom on either side of the back of the car, and saw no faults and anything wrong. However i did notice that the colours of the wires leaving the brake light switch plug are White with a thin green stripe and the other green with a thicker grey stripe. when looking at the taillight plugs(both of them) i did not see either wire. i will try look tomorrow and see what colours there where. however, i plug the lights in again and all was fine. placed the lights back checked again - fine. removed the bridge on the brake switch plug and put everything back to normal, then re tested and there was nothing again.
So i removed the lights again, this time not knowing what it could be. the brake lights never came on this time during removal(same as before, drivers side first)

Then while i was milling around not really knowing what to do, i thought id reconnect the lights 'partially' - not letting the plug clip into the holder(for quick removal. when i did this, again the lights came on, so i pushed the plugs all the way in and everything was still working. i wiggled the plug+wires for several minutes(quite hard as well) and they stayed on so didnt think more about a loose wire in the plug. i left the brake lights one while i reinstalled everything and to my excitement, everything stayed on. that is until i tried testing. when i finished installing everything back to normal, i went and removed the bridge on the pedal switch plug. the lights went off as expected, then when i put the bridge back they stayed off. no amount of wiggling or tugging etc made any difference.


I am at my wits end now with this and have absolutely no clue what to do. if possibly id like to see a wiring diagram and possibly have some1 explain how the system works.(it puzzles me as to why they came on when i was working on the passenger side in both occasions) it is my understanding that 12v is supplied to the brake pedal switch plug. when that is plugged into the switch, and the pedal depressed, the circuit is closed allowing 12v to the brake light bulb holder, turning them on. Both holders are linked - i.e power runs to the drivers side first for example supplying power to it, and from there it runs to the passenger side as well. My friend suspects it could be a possible sticky relay although im not sure if there is one in the brake light circuit?

Please help guys, not sure what my next step is to do other then send the car into an auto electrician(im an apprentice electrician myself) and id really hate to have to strip the entire car out just to bloody trace a wire(striped it a few times before so kinda tired of it haha).

looking forward to hearing from you guys and hopefully finding the problem to my solution.. Much thanks in advance.

Skar-ZA

bump - anybody??

Skar-ZA

nearly 210 views and nothing?? have i got everybody stumped?

Skar-ZA

i find it hard to believe that it can have this many views yet still not a single reply... wheres the "resource" of knowledge??

jbpnoman

If you've already checked all of the wiring, and you're getting proper voltage and good ground, the only piece left to check is the brake light switch. Remove it, and test for continuity with the button released, and pressed.

Former User

The brake light circuit diagram is shown below.

In short, the circuit looks like this:

1. Coupe, sedan, or hatch? I'll assume it's a coupe (please verify).
   
2. The fact that the taillights always work suggests that the rear G601 ground is fine.
   
3. I will assume that when the brake lights do work, all brake lights work rather than just certain ones (please verify).
   
4. If (3) is true, then logically the problem must be located upstream of the splice branch to all brake lights.

Troubleshooting strategy

When the brake lights don't work with the switch bridged, test for battery voltage at these points in this order:

1. C563
2. C401
3. C442
4. The switch connector
5. Both top test tabs of fuse 52

Stop testing at the point where battery voltage is found and post the result.

Skar-ZA

Thank you! Thats a great help. i will go through that and give it a go - this will require a little studying on my part. Question tho, C563 location. will it be in the same place on the coupe(i notice to picture is a sedan so not sure if this will be of any concern?)

to confirm the points:

Coupe, sedan, or hatch? I'll assume it's a coupe (please verify). Coupe
The fact that the taillights always work suggests that the rear G601 ground is fine.
I will assume that when the brake lights do work, all brake lights work rather than just certain ones (please verify). Correct - both work as per normal
If (3) is true, then logically the problem must be located upstream of the splice branch to all brake lights.

Former User

Same for coupe and sedan. You're looking for the brown 2P C563 connector that passes through the driver-side quarter panel. Also inspect the harness downstream of C563 until you reach the splice branch.

Skar-ZA

thanks a lot - ill give it a crack this weekend if i get some time(something i need a lot more of lately.)

Skar-ZA

Thanks to those that helped. i went through everything, all my grounding points where fine(stripped the car for nothing lmao)... ended up taking the car in to the mechanic to get something else looked at and thought while its there id get them to have a squizz. Turns out the switch connector wasn't making good contact(from the fuse box to the plug) so while it was able to supply 12V to the lights, it wasn't able to hold the load(current) to turn them on.

Guess you learn something new everyday - experience is gained soon after it is needed most. Thanks again to all those that helped....