hey guys im hoping someone can answer me, my 2004 blazer 4wd has towing package from factory far as i can tell, the trailer lights have no power (trailer works fine on other trucks) i checked fuses under the hood in the distribution box and trailer fuses are dead none blown is there a module or another relay or maybe a wire unhooked maybe even a bad fuse block, im just curious i know on other models from different makes you cant have a control module out causing this issus

 

Possibly a bad connection on your truck's connector? A bad ground would keep all of the lights from working.

 

Trailer light circuits have their own fuses in the underhood fuse panel, (5 of them). To test the fuses, the ignition must be in the RUN position, headlamp switch in the ON position, and the 4 way hazard switch in the ON position. With a test light or DVOM, test both terminals on the top of each fuse:



The trailer park/tail fuse should show constant battery voltage. Left turn signal and left stop lamp use the same fuse. It should show voltage alternating from zero to battery voltage. Right turn signal and right stop lamp use the same fuse. It should show voltage alternating from zero to battery voltage. The CHMSL, (chassis high mount stop lamp) has its own fuse and should show battery voltage only when the brake pedal is applied. The trailer brake should show battery voltage only when the brake pedal is applied.