Help! Brake lights won't work...

tstring · 06-22-2009

About a week ago I was told my rear brake lights are not working. I checked the bulbs, the fuses, changed the brake switch; twice. All other lights work - turn signals, hazards, reverse lights, etc. Just the two brake lights. I have read about a harness relay plug and a brake relay - but have had no luck finding any information about either one.

Thanks!

To remove this ad, register today for free or log in if already registered!

gearbox · 06-22-2009

how did you check the switch? cause usually the brake switch is the most common cause for the lights not working. or you could have a broken wire. just gonna have to trace back the wires from the rear to front. and maybe run new ones if you have to.

tstring · 06-22-2009

Checked it two ways - first, the brake light in the rear window still works, it did not when the switch was removed, and second I went and got the reader to make sure it was getting juice.
However, this afternoon while I was tinkering I was hearing a 'click' while depressing the brake - from the gear shifting area (automatic). I understand the tail - brake lights have a different power source than the one from the rear window brake light. Am I just hearing the rear window light relay kicking in? (The car was on, not started, that's how I could hear it.

Oh, and I made sure the horn works too. It does.

gearbox · 06-23-2009

at least on the 01+ civics, the top mount brake light is spliced into the passenger side tail/brake lamp wires. i traced them and found out, but yours may be separate. the click you hear is just the gear shift lockout. basically the mechanism that prevents the shifter from being taken out of park unless the brake pedal is pressed. that is not related to the brake lights. i would start by tracing the tail/brake lamp wires and see if everything looks good, including the grounds that are connected somewhere under the plastic trim pieces of the trunk liner.

CraigW · 06-23-2009

Brake lights are all on the same circuit... just different tap points all use the same wire color which is WHITE/BLACK.

If the taillights are working the grounds should be o.k.

You will need to trace (no) voltage back to the open connection. There looks to be a connection that has all three together (left/right high mount)

tstring · 06-23-2009

Started in the trunk - checked the wires in the trunk casing - all okay. Then, went to the front and to my relief - only 1/2 hour into it - found three relays behind the glove box.
Dealership, manuals, and the 'book' from an auto parts store said nothing about these relays. ****!
But, there seems to be a blue plastic 'holder' under the relays; two in one and one individual. They would not budge in order to use the test light.
Is there an easy way to remove the exterior of the glove box to get to the wiring for these relays so I can test them?

One more thing, if these relays do work and I still can't find the problem, couldn't I run two new lines directly from the brake switch?
Thanks for the help!

gearbox · 06-24-2009

those two pieces on the side of the box should pop out so the whole box will rotate down to the floor.

CraigW · 06-24-2009

If your high mount is working... you have voltage back there at some area. My schematic shows it as a single line to a certain point (maybe in the trunk) and then a 3 way tap/split from it.

tstring · 06-27-2009

The three relays are slide-clipped to the metal frame behind the glove box AND each relay has a side-clip as well. Removing the glove-box completely helps tremendously in order to accomplish this without losing a finger.

I had a bad fuel pump/main relay...Any guesses as to how my car was still running?...maybe another day...ANYWAY-

Order the relay-car runs much better and sounds much better but I still have no brake lights.

Any word on just connecting two new lines directly from the brake switch to the tail lights themselves?

Thanks for all the info!

brokedown711 · 06-27-2009

sure, you could run a new 12v line directly from the brake light circuit at the junction to the lights... but that wouldn't help you figure out wtf is going on. find where the stock wiring splits off into the 3 lines (left/right/3rd) and go from there. it can't be much wiring or difficult to get to if it's by the back seat/trunk

CraigW · 06-28-2009

Like I said, if you have the high mount light that is working you have voltage in the trunk area. You can tap in there and run it to the rear lamps. The brake wire color is WHT/BLK.