Both 2003 oddyssey brake lights dont work High

The tail light fuse is under the rear seat on the drivers side.

If the high mount brake light is working, the brake light switch will be ok. The brake light circuit usually runs through the signal light switch on most vehicles. You may have a defective signal/multifunction switch causing this problem

check the light checking unit power for light go through this to the bulbs tell you when a bulb is out. center light is not on this circuit.

Nope, high mount comes directly from the brake switch, the other two come from the brake switch to the turn signal switch then to the back, seen a couple of the circuit boards bad in the tail lamps, if one side is working good try plugging the good side into the other side and see if it still works, if so its the tail light.. P.S. if vehicle has trailer wiring double check that too, usually that's a huge issue...

The circuit to the taillight brake bulbs goes through the turn signal switch. Sometimes the switch can cause this problem.

does the high mounted brake light work? the brake switch has 2 contacts one for the high mount (LT BLUE/BLACK) and one for the tail brake lights. The tail/brake light wire is LIGHT BLUE. the main connector between the brake light switch and the tail lights is C208 which is located behind the rear seat, left side. So if there is power coming out of the brake switch OK and no power at the tail lights, check that connector. Hope this helps.

I've worked on these the first drove me crazy. its the turn signal switch every thing runs thru these. head lights, turn signal, brakes. except the third brake light. it runs directly from the brake switch. go figuare

make sure u have put the right bulbs in. rear brake lamps are dual filament....

theres usually a pressure switch behind the brake pedal, sometimes the plastic hex nut rattles loose and you have to retighten it.

Could be the brake switch that is mounted to the brake pedal area. Check if you have voltage out from there when brakes are applied, there may be two leads one for the high mount and one for regular brake lights.