tail light blowing fuse: after car stereo install

In need of help 1984 d50 miniram. removed stock radio. installed agter market radio. ran new primary wire from battery to hot lead on stereo. no issues with stereo. when I turn on the truck lights, the tail light fuse blows instantly. the headlights, and brake lights remain working.. only the tail light wont work. read somewhere that there is possibly a wire on the same circuit with the tail light fuse that sends illumination ? to the radio? not sure if that applies to my truck. read it on fixya. if true, do I need to locate the wire? which one? and disconnect it from fuse panel, in case it is grounding out? have not pulled the stereo back out to look at old unused original radio wiring yet. I am pretty sure the tail lights were working proper prior to stereo intallation. any help please?? email is augierockstar@gmail.com thank you in advance.

I am betting the stock radio "illumination wire" is grounded where it was cut. Pull the stereo back out to locate the wire that becomes "hot" (using a multitester) when the "running lights" are switched on.

Welcome to the forum. :) Let us know how things progress with your issue.

x2 on the illumination wire grounded for the radio.