Taillights not working-keep blowing fuse

I can probably guess which fuse you mean, but if you could identify it specifically (like, by its position, or the legend for it on the fuse box cover) that would be better than me guessing, and it would save any wasted time if I guessed wrong.

Are you saying it blows whenever you turn the car on, whether the light switch is on or off?

The lights normally will work even when the car is off. What happens if you turn the light switch on then?

 

Well THAT will certainly not fix it.

There is a short to ground somewhere in the wiring for the tail lights.
It could even be a short INSIDE one of the tail light bulbs.

The first thing to do would be to remove ALL of the bulbs on that circuit, which probably includes the license plate light and any side markers that might be present.
IF the fuse still blows, then you have a pinched wire somewhere.

 

For a fault like that, first I get the wiring diagram and study the circuits involved- see where everything goes. (Helps me to print out the needed pages and mark things with a highlighter).

Then I use (or make) and adapter that replaces the fuse- each leg of the fuse goes to a wire. I connect the two wires across an incandescent headlamp bulb. (I prefer an old school sealed beam- it's less likely to melt anything around it). The bulb replaces the fuse, and if there's high draw on the circuit, then the bulb lights up brightly and limits current to about 4-5 amps.

If the short is active, then I start inspecting the wiring, wiggling and moving the harness, and unplugging things to see if it affects the light. (If the short is removed then the bulb may still glow some- depending on what the normal current load is on the circuit). Where I look and what I unplug will depend on what the wiring diagram shows me.

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An easy way to make that kind of adapter is to start with a Fuse Buddy.



(The same principle as the easy way to start a fire using two sticks: have one of them be a match.)