Gifting my current daily to someone who needs it, and picked up a '94 Civic DX coupe, 5 speed, no cruise as a daily. The brake lights do not work, at all. So far, I have checked the underhood fuse, both visually and with a meter, replaced the bulbs, and checked that the brake switch rubber grommet/stopper are intact. The car is totally stock, never been hacked up at all. Any ideas?

 

Have you checked out the actual wiring of the headlights? Maybe something is going on there

 

Check the plugs for continuity and voltage.

 

I'm assuming you also checked the rear grounds?

The continuity test NotARacist suggested should indicate bad grounds or shorted wires.

 

will get to it asap and post results.

 

weather here was crap today, didnt get to poking around. should be mentioned that the tail lights DO work, just not brake. probably unrelated to the issue, the left turn signal works only when it wants to. bulbs are good.

 

replaced the switch for good measure, no dice. jumper the two prong switch connector, nada. have power @ fuse, brand new switch, and jumping the connector produced no result. the lights should have lit up without the switch with the plug jumped, correct? if so, my problem would have to be somewhere between the fuse box and switch plug?

 

 

there is no issue with the plugs, as the tail lights (dual filament bulbs) do work. the issue is somewhere between the fusebox and brake switch. due to a lack of time, i ran a fused wire from a free pin in the dash fusebox to the input wire on the brake switch. the brake lights now work as they should. ill be tracing wires sooner or later, if anyone else has had a similar problem feel more than free to tell me what your fix was.

 

I just got my ETM in the mail the other day.

There is a massive junction after C590 where all the wires split to all the brake lights.

You are looking at the Green/White wires from C423 (that's from the brake light switch right by the steering column) C423 runs and connects to C417 which splits for cruise control if you have it. C417 then runs to C415, C415 goes to C590. After C590 it splits like I said into all the lights. For the whole route it's always the Green/White wires for the brake lights.

I would check those connectors to see if any of the have corrosion on the Green/White male/female connectors.

After that I would be trying to find that massive splice after C590

C417 is a 20-White Junction connector under the left kick panel.
C415 is a 15-Grey connector below where the cruise control unit would be or is also under the left kick panel.
C590 is a 20-Grey connector behind the left side of the rear seat.

Not sure how far past C590 the major splicing is but every tail light is tied in at one spot by what the ETM is showing.

And like I said, the color wire you are after through that harness and connectors is the green/white.

Hope this helps.

Cheers.

LoL wow, I type all of that and then I see, it's the wiring before the brake switch.....

Gimme a sec..

Under hood fuse 42 to C202. White/Green wire from C202 to C417. White/Green of C417 goes to the brake switch. Other end of the brake switch is then the green/white that goes back to C417 and heads to the back of the car.

C202 is 2-Brown on the back of the under hood fuse box.

Of note fuse 42 runs both the brake lights and the horn so if both are not working you know to look at the fuse.

The section you seem to have issue with is the White/Green wire. From the back of the under hood fuse box to the C417 under the left kick panel.

Also of note the White/Green wire of C417 also goes to the interlock system.

 

hey i appreciate the help, and the info wont go to waste if someone actually uses the search function to diagnose this problem in the future. ill get to probing around when i have a bit more free time. for now, the free pin/fused wire setup is working out ok.

 

Is your hazard light plug connected by chance to the correct plug? I mixed up my clock and hazards before and had no turn signals and no brake lights

 

yes. the right signal works fine. ill be attacking that issue sometime this week.

 

I've seen this type of behaviour when there's a bad ground. Brake lights and turn signals get confused. I think grounding begins happening through other wires and things get bunged up. I've seen Ron@HT explain it well in past threads.