Why Don't I have no brake lights on my 2003 chevy hd 2500 .

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

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Did you check the park fuses, note the diagram, rr and lr. Use a test light to check voltage at fuse circuit, headlamp switch on. That should tell us if problem is before the fuse or after.
You always want to check voltage and ground circuits, for lamps. Do the front park lamps work?

feed supply problem somewhere ?but where ? try checking the wiring loom at the rear or as its called in american "pigs tails"

1. Check fuses

2. Check for corroded/broken/damaged wire under(especailly if it has a towing package harness add on) the vehicle and around the light assembly even under the carpet especially if the vehicle is rusty.

3. Check the sockets and circuit boards(sometimes the sockets are built on a circuit board) for water/corrosion inside.

check for power at the wires going intop the tail lights, real common that the circuit board is bad, but unlikely both at the same time. The tag, tail lights and brakes are 2 different systems. Do the turn signals work normally? if so the wiring from the turn signal switch to the brake lights is GOOD. the stop light switch had\s a ORANGE wire that should have 12V if not ck STOP LPS fuse, when brake pedal is depressed, the WHITE wire is 12V (at the stop light switch) if that is OK, the turn signal switch COULD be bad. The wiring harness plug is near the back left under the tailgate, see if that is disconnected?

First let's determine which brake lights are not working. Does the high mounted brake light work? Do both left and right brake light not work? If none of the brake light work, the problem could be the brake light switch at the brake pedal OR fuse #12 in the underhood fuse panel.
If only the bake lights at the corner lamp assembly don't work, check fuse #34 in the rear fuse panel.
The module your are referring to is the circuit board located in each of the corner lamp assemblies, check on website www.compnine.com for the part number of this item. I don't believe this is your problem though.

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

I had this problem, and to be honest, it happened to the left side about a week later...it's the board that the bulbs plug into...it's a very common problem with this model. So popular that you can normally get the socket board off the shelf at a parts store! it's extremely simple to replace, and I replaced all the bulbs at the same time!

You need to replace this:

Solution to your problem ... 1- I purchased from 1aauto.com a pair of Circuit Boards for my Chevy Venture 2003 for 85.00 $ ..free shipping 2 - I Installed them both , all lights now were not working at all. So I checked them and they were all burned ...So I purchased new ones ....Everything was working fine now but now my signal lights were not working left and right .....Checked the fuse box next to the passenger side door .... It was burned . Changed the fuse / Signals are working fine now ....All is good I just did this yesterday evening August 12, 2008 Conclusion ..Change everything going forward so you do not need to run around like I did from one store to another!

1. Circuit Board : New
2. Bulbs : New
3. Fuses : New

Thank you