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HELP! Brake pedal keeps blowing fuse (HORRIBLE UPDATE)

Hi, all! I’m hoping someone can help me. I have a 2003 Honda Odyssey and every time I step on the brake pedal, it blows my STOP fuse under the hood (which takes out my ability to shift out of park, use my horn and the brake lights also go out.) When I replace my fuse, the horn does not blow the fuse, it is stepping on the brake pedal one time, even when in park before turning the key over.

Things I have tried: Changing all of my bulbs and inspecting the socket areas, inspecting most of the wiring and taping areas that seemed fine but might have been touching metal, replacing my brake light switch.

Any ideas on what could be doing this?! I have figured out that I can manually shift out of park using the override slot, but no brake lights is not good.

Thanks, friends!


I would check the grounds on your circuits with a test light.

Has there been any work done on the wiring recently?

Sometimes the insulation on brake light wires can wear down and can touch and blow a fuse every time you step on the brake.

Check the brake light switch above the brake pedal for a short.

If there were poor/no ground, the circuit wouldn’t pull enough amps to blow the fuse.


When you say check the brake light switch, do you mean the wires that connect to the switch or the actual switch? When the new brake light switch didn’t work, I took it back to AutoZone and they compared the new and old switch, checking all of the terminals (my terminology might be way off) and the voltage read the same for both switches, which makes me think that they both worked.

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Nope, no work done at all.

When you say test the grounds on your circuits, do you mean test the grounds on the wires of the brake lights?

Thanks for the response you guys. I appreciate it immensely.

If this vehicle has an add on trailer hitch look for poorly routed wiring especially near the exhaust system.


Nope. But I’m glad you mention that, in the event that it could help someone else who happens upon this thread. I have read that trailer hitches can be problematic. Maybe because they are often DIY jobs?

Thanks for the reply.

About the only advice I can offer involves disconnecting some wire plugs and noting when the fuse popping stops. This can be a bit difficult to do without a factory wiring book which shows locations of connectors and so on.

The other option is wandering around the electrical wilderness so to speak and I absolutely loathe wading into an electrical problem blind without perusing a schematic first.

Helm publishes various manuals that are excellent and often used by car dealers. The issue there is price at probably 50 bucks for an electrical manual but they can be invaluable as they’re laid out well and show the location and color code of every wire and connector on the car.

I’ve bought a few off of eBay on the cheap so that’s a possibility.
The above is likely not of much help but with a short and no hands- on situation it can be near impossible to guess at the exact cause.

For what it’s worth, when working with a fuse popping situation I often use an old automotive door chime which is plugged in with jumpers in place of the fuse. It saves going through a box of fuses and encourages one to work faster so as to shut up that infernal ding-donging… :slight_smile:

Here’s a diagram for '06-'07 Civics. (MICU = Multiplex Integrated Control Unit) It’s a simple circuit. Obviously, the problem is getting to the (in this case light green) wire over the length of the vehicle. If the wire goes through any hinged areas (rear hatch?), that would be a place to start.

great ideas, ok4450.

insightful: Thank you for the diagram! My odyssey is very similar to that, and it does use a green/white wire all the way to the back. Also, there is a hinged area by the liftgate encased in a rubber sleeve (boot?) and I have not looked inside there yet. How do I get the rubber off without cutting all of the wire on one side? If I just cut the rubber off to look inside and possibly fix any problem, can I tape the rubber back together, or will the rubber not move right?

First make sure you have brake lights on your hatch. I’ve never messed with wires in a boot. It would be best to slide the boot one way or the other to expose the wires. Cutting the boot should be a last resort.

When in situations like this, I sometimes use an old sealed beam plugged in, instead of the fuse

If it’s bright, the short is still present

When it goes dim, the short is gone

If you “join” the autozone website, you’ll have free access to car information, including some wiring diagrams. They’re not great, but it’s free

And they will not ask for your social security number, credit card number, etc.

You can buy online access at and it’s worth every penny of $26.95 to get the correct prints. Unplug all your bulbs and install them one at a time until the fuse blows. Don’t forget the high tail light on the tailgate. That should narrow the problem down to which circuit.

How would installing a bulb cause the fuse to blow?

I do have back lights (as in, when I turn my headlights on) so there is power going to those bulbs, even with the fuse blown. But no brake lights. And stepping on the brake pedal is what blows is.

Thanks for all of the tips so far. It’s been raining ALL DAY so I haven’t been able to do much.

knfenimore, I’ve removed all of my bulbs to try that and even with all of the bulbs removed, the brake pedal will still blow the fuse.

You must have a dead short a wire between the switch and the bulbs. At this point, @insightful’s advise is the best so far. The wire harness must be traced to find the short.

I would bet money that you have damaged wires, especially for the third brake light, where the wiring runs from the body into the tailgate.

A thought on the trailer hitch idea: Could a previous owner have installed, then uninstalled a hitch? If so, (and really, in any case) look long and hard under the rear of the van for any wires that could be suspect.

Put in a new fuse, then have someone watch the brake lights as you step on the brakes. See if one brake light does not come on before the fuse blows. Two of the lights should at least flash momentarily. This will isolate the circuit where the problem is. If none of the lights flash, then use a larger fuse or a piece of wire in the fuse socket, but only hit the brakes for less than a second, just enough to get the brake lights to flash, no more.

If they all come on the same or none come on, even for a moment, then the issue is before the junction where the three circuits split out. That is most often at the split or at the brake light switch. The brake light switch could have an internal short and unless the van has been in an accident, this would be the most suspect.