My 82 j10 has never had signal lights that worked? I had the tilt column out, (bad slop in bearings), for rebuild. It had no signal light harness, so I replaced with new. Now the mechanics work, but only the front lights come on, And they don't blink(new electronic flasher installed). Tail lights work, brake lights work. Wiring under dash has benn messed with by PO. All other electrics work. Light in dash comes on when signal lever is flipped, just no rear, or no blink? Where do I began?