Try your fuses
and that didnt fix the problem?
Fuses blow when there is a short circuit or an over current condition.
The 2002 Chevrolet avalanche horn and trailer lights have different fuses. The fuses can be found in the fuse box. The location of the fuses can be found on the inside cover of the fuse box.
Under the dash left of steering wheel
The block heater is standard on most Trailblazers. The cord is attached under a flap against the battery.
The fuse for the dash lights on a 2002 Chevy Tahoe is in the fuse box in the interior of the vehicle. There is also a fuse for this in the engine compartment on top of the battery. This fuse is for the speedometer and odometer lights.
The 2002 Cavalier has a reverse light switch. The switch can be bad, or have a loose connection causing the lights not to work.
The courtesy lights solenoid (relay) of a ford galaxy 2002 is found on level 1 of the junction box underneath the drivers dashboard together with most of the fuses. If the courtesy lights are'nt working first check the fuses. There are 3 fuses controlling the interior lights, numbers 27, 53 and 55.