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Honda brakelight puzzle

Hi everyone. Hope someone can help me here.

I have a 2003 Odyssey with suddenly no brakelights except for the middle “cyclops” brakelight. Fuse is intact as are the bulbs. I’m assuming the switch is good too since the cyclops light comes on at the right time.

Anyone have a clue as to what’s going on?

Thanks much.

It may be a broken wire in the back. Start at the brake lamps and follow the green wire to the ‘brake light failure sensor’.

Are the brake lights attacked to the trunk lid? If so look where the wires come from the car to the lid. Likely the problem is there. If other lights are out that are located on the lid, then look for a bad ground.

I assume you’ve tried new bulbs?

The only way to definitively do this is to check at the socket with a DVM or test light to see if you have voltage at the proper contact when the pedal is pushed in. You can block the pedal down with a 2x4 enough to allow the brake light switch to activate. If you have two filament lights, one for brakes and the other for taillights, you’ll need to see with the DVM which terminal is the taillights to (by the process of elimination) know which is the brakes. If you have seperate bulbs it’s easier.

If you find voltage, check the ground sides of the sockets to see that you haven’t lost ground.

From there, you’ll need to trace backwards at every accessible point to find the missing voltage. Hopefully you won’t need to unbundle any harnesses to find the problem.

Joe, FWIW the Odyssey is a Honda van. It has a rear hatch (not a trunk lid) with no lights on it.

The bulbs are two element brake/tail lamps. The green wire is carrying 12 volts which has come through the brake switch, through the brake light sensor to both corner brake/tail lamps. If the tail lamp works, the common ground is good. Push the brake pedal and check for 12 volts on the green wire that connects to both of the corner brake/tail lamps.

Hi and thinks for your insight and information.

If my brakelight failure sensor is doing its job (which it currently is by dutifully informing me that they’re out), then does that help locate the failure any more?

although you state. “the bulbs are intact.”…

the light bulb alarm is telling you otherwise.

first off, put NEW bulbs in. they cost about 3.00 a piece. try that first, then get back.

at a minimum replace ONE with a new bulb. that is the easiest, cheapest thing to do.

it may be something else, but for the cheap easy thing to eliminate out of the system, go for the bulb.

The brake light circuit runs through the the flasher unit so the trouble may be with it.