Bringing up an old thread, cause for some reason no one seemed to mention how to wire the clock, when I was searching before finally wiring one up. I've got an 82 2x4 wire harness in my 84 runner, But there actually should be a plug and play for the newer trucks. unless some jack ass used it for the radio.
Maybe its just mine, but the damn thing is labled if you unplug the harness from the clock and look at the printed board. top left is L+ Red/Green. Top right GN White/Black. bottom left is D+ green/red. Bottom right is C+ black/white
So L+ is hot switched, which I put with D+ Dimmer, Im assuming that 12v would make it the brightest, (let me know if im wrong) C+ is constant hot for memory, and of course GN is grounded.