2003 Chevy Silverado SS brake lights aren't working but top cab brake lights are. Bulbs in brake lights are working, and light up when headlights are turned on, but do not get brighter when brake pedal is pushed. Fuses are fine.

sounds like a bad turn signal switch . both side brake lights run through it but the third brake l;ight runs direct from the brake light switch .- play with the hazard button a few times and if the start working you need the turn signal switch

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

If all bulbs are good is most likely printed circuit board that bulbs plug into, very common to go bad. HELP/motormite sells them in 2 pack for both sides. Available in any auto parts store for less than the dealer charges.

check the bulbs and make sure the socket is not rusty or dirty

check grounds on rear light assy's

the source of this problem is the turn signal switch
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Source: rockauto.com

ljones, Did you check the "VEH stop" fuse in the left side instrument panel fuse box. There are 3 stop light fuses, 1 for all the stop lights located in the under hood fuse box. 2 in the left side IP fuse box. 1 for the upper stop light and 1 for the lower stop lights. The fuse box in the IP is where the upper and lower stop lights split. Let me know.

There is a probable bad wiring connection in problem one and three.
#2 Possible water leak causing bulb break. Try wd40 in socket. you need a wiring diagam and cheap voltmeter if you want do it yourself.

It is a common chevy problem for the circuit board that holds to bulb to fail, are your running lights and signals still working back there as well? If not then you need to replace the boards.

Replace the headlight switch, it is probably causeing a short....