How do i change 3rd brake light bulb for 2007 hyundia accent

If all the brake lights come on ( including high mount ) with the headlights there is most likely a short somewhere. Have any of the park/brake light bulbs been changed recently. If so a bulb may be installed incorrectly or the wrong bulb application used.

check brake fuse. if its good then you need a new brake light switch, its located on the stering coulom above the brake peddle

No, the third (3rd) brake light is on the same circuit as the other brake lights. So, knowing this, there must be some other cause.

1. New bulb is also bad
2. Bulb socket is damaged
3. Power/ground at the bulb is not present (in which case, locate the fault).
4. If all else fails, Take the vehicle in to an authorized Hyundai Service Department and have it properly diagnosed -- this way you'll know EXACTLY where/what the problem is/was and the parts/labor required to fix it.

check for bad brakelight switch on the brake pedal under the dash,but on the brake pedal rod,will be a switch that has a pluger that pops out when you apply the brakes,check to see if it's plugged in. other than that,just replace the entire switch,yhey do go bad often enough.

Check for corrosion inside the bulbholder.

There was recall for the 2006 and 2007 Hyundai Sonata Brake Light Switch assembly. www.promanuals.net

get new light bulbs

ON MY HYUNDIA, IF YOU OPEN THE TRUNK AND LOOK UNDER THE LIGHT, YOU WILL SEE 2 NUTS THAT ARE RECESSED UP UNDER THE LIGHT. THAT MIGHT HELP.

are the rear lights combined? ie sidelamp and brake lamp in one bulb .if so, there is a possibility that the bulb is not sitting correctly in the holder , causing both the side & brake lamp fuses to blow . if they are seperate bulbs you probably have ashort in the sidelamp system somewhere but the brakes could be a switch problem [easy check, find switch ,disconnect wires short across using wire or paperclip switch on ignition and check lights ] if they work the switch is the problem , [check fuse first] if they don't

hiya to access the bulb on high level b/light with hatch back up you will see the shroud/cover surrounding the lamp ? this cover is a clip on to remove it just hold the cover on both side/ends and pull/slide the cover down keeping against the screen it is easy ! and you will see the clips and where they clip on? the actual bulb is removed by twist anti clockwise the socket and pull out of lamp the bulb is a larger version of the push in type bulbs as fitted to small sidelamp front bulbs on most cars be sure to replace the bulb with correct type ie 16 WATT refit new bulb and check operation before you refit cover/shroud ps now would be a good time to clean rear screen area not accessable with the cover in position ?? best wishes