On my 95' GMC Seirra P.U., my tail lights stop working and i dont know. How can i fix it? I changed the bulbs and checked the fuses...Will someone please help me!?

The standard wiring plan for towing may not have been used on either the towed vehicle or the tow vehicle. If you had lights for the vehicle you were pulling, you must have connected them to your vehicle. Is that a fact? If you have lost power to them because of fuses? You may have caused them to melt. If you have a weak grouind, no ground, crossed filaments, bulbs out, socket trouble, or bad circuit boards, you have to remove the taillights for access and get a schematic for the wires that is specific to your model, year, and the kind of parts in use. You might google that and find one thru a parts website to view online. Next you must observe the items in question and define what it does. Operate every function and write down what you notice that is light related turn signal related or light switch or brake pedal or cargo lamp related. You can pull all the lights and go thru and inspect them all for burnt, wet, milky, improperly installed, or crossed filaments. Check every fuse, the interior, the power distribution, and the inline fuses and fusible links or maxifuses. Make a parts list and bring your old taillights because you might have to address circuit boards or the switches that send power there. verify a ground everywhere the schematic shows one. check ant towing wiring or add ons you may have. Study your schematic. learn what gets what from what. If you start guessing, it can get expensive. It is your truck and your money. I believe your GM dealer may have the answers quicker but since there are so many schematics and changes by year and equipment, you may have to pay someone to get your specific cause on your rig. Buying the simple tools for testing and the drivers for the fasteners They use may assist you better as you study the circuit map from the schematics. They keep rewiring it, they change it often, unfortunately you have your patience to thank for any personal success.

Check out your towing wiring, not, check ant your towing wiring. If you lose taillights when activating headlights, make a note of that. If turn signal blows a fuse, make a note of that, these are the kinds of things to look for when defining your issues.

a guy reminded me on another thread, the battery grounds to the block and the body, the frame has to ground to the powertrain, either the engine block or the trans area. The bed or the cab may need ground verification. Gm likes to play with what has what or does what from year to year so they can shave cents off their minds. You must have less than .5 ohm for any wire that is considered a good connection, and less than .5ohms to ground at any ground. The library has free books to read if you cannot pay a technician to do the figurin.