You should never connect any accessory directly to the battery in a car. If a short happens, you will have the full current capacity of the battery routing through the passenger compartment. The current capacity of a car battery is enough to melt a solid copper 14 gauge wire in a flash. This can easily start a fire.
If you must, go to an auto parts store and buy an in-line fuse kit. Put a 25 or 30 amp fuse in it and use no smaller than 18 gauge wire in your new circuit.
rear lights and dash lights should be on the same fuse, check your owners manual if you have it.
at the back of the firewall 4 relays lined up.
CHECK THE FUSE PANEL DASH & TAIL LIGHTS WORK FROM SAME FUSE
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#12a
1st move the light switch to the desired position. 2nd PULL the switch gentle towards you. There are two positions for this switch. The first position or click, will turn on your front running lights. The second position or click will turn on both your front running lights and additional lights in the rear. You will be able to tell that you have activated them by the icons on your dash that will inform you they are on. To turn off simply push the switch back in. (Actually, those are the FOG lights, front and rear.)
Try checking the tail light relay.
It's a 20 amp mini fuse #37 in the fuse panel under the hood on the passenger side fender well. It is labeled "Parking" in the fuse diagram, and if blown will cause you to have no dash lights and no rear running lights.
Be sure to keep the rear tail lights, brake lights and signal lights in good working order. To many times you see vehicles with lights missing.
Generally brown is used for running lights, green for right turn and brake, yellow for left turn and brake.
you have a blown fuse, look in your owners manual and it will show you the fuses location.
Which connection? The dash is in the dash, the tail lights is in the rear hatch area...you can find a wiring diagram and info in a shop manual at the library...you need to make copies as they are reference only...:)