why are only the tail lights on my 2000 nissan frontier not working (i have- blinkers, brake lights, reverse lights and cautions lights)?

yes...insufficient ground to the chassis...what you must do is find the end of the Black 1/0 Battery cable (not the clamp end, the other end) that has a lug...grab the lug with a pliers and wirebrush the lug and territory where the lug came off of with a wirebrush...this will restore ground potential with your NEW battery....because the newer tin/antimony alloy batteries will stop taking a charge ten percent per year...in ten years will not take a charge anymore....so improve ground potential with the renewed chassis ground...test the voltage at the components....should see the full 12.5-13 VDC~

Thanks, I will try that after work tomorrow!

Yeah, don't try that after work tomorrow. Your problem may be a ground fault but it has nothing to do with your battery cables. Your car starts, I assume. The solution presented by the robot above is actually a pretty good answer for a starting issue based on a poor ground connection at the battery. I've read the same answer on this site for three days (I'm new here) applied wrongly to several questions. Might be a glitch or something else. Your problem might be an intermittent short. Usually this is a short in a positive D/C wire that just overheats and then resistance blocks the current. When the wire cools down, current flows again and everything works. So let it cool down. That sound right? Have to go to bed now but let me know.

There is a tail light fuse in the fuse box under the hood next to battery. Fuse probably blown. If blown tail light fuse also means your dash light will be out as well. Replace fuse and both should work.

what is the fuse number and how many AMPS?

Sorry did you fix the problem? I am having the same problem right now