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Q: wiring harness information on 2003 Chevrolet Trailblazer

The right brake light works fine, the left does not; both bulbs replaced in the left light assembly, taillights and left turn signal now working so the bulbs are correctly installed.
So far as I can determine, both brake lights are on the same fuse, so that can't be the problem.
Where does the brake circuit divide? Are there two separate brake light wires coming off the brake switch, or one wire which later divides? And where is this divide located?
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their is only one fuse for the brake lights of your vehicle. that would be fuse 34 in the fuse panel behind the drives seat, under the back seat. Theri are also fuses 43 for the right turn signal & fuse 38 for the left turn signal you may want to check these also. If your brake light is only working on the left side but not the right side you can check out if your rear bulb assy. is bad. Put a 17 to 18" stick on the brake padel and slide your seat forward to hold the stick to keep the brake lights on, use a 12 volt test light and check the plugs that the bulb goes into, if it does not light up test the "Lt. blue wire" if you have power the bulb assy. is bad and needs to be replaced. Also a note if you replace the right rear bulb assy pay the extra and get the left also it will go out too. These were on recall and may be replaced for free take the vehicle to the dealer they will scan your vin and look up all the recalls for your vehicle. And the last thing because I see this all the time, please insure you have the correct bulbs for your vehicle and light all the lights on your vehicle have their own number, brake lights, back up lights, turn signals, etc. all different. Tj; Fire Equipment Mechanic
Finally took it to a repair shop; they replaced the bulb holder assembly. I don't quite understand why I couldn't get a voltage on the light blue wire with the bulbholder assembly disconnected, but their fix worked, so anyone else having this problem, be aware of what worked for the repair shop.
Thanks for the advice.
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