Tach wiring

Hi I just got a 99 extended cab with 3.0 and 5 speed. No tach so I installed an Autometer tach, however I can't find where to hook the tach light into the instrument lighting.

Does anyone know where I can tap into this? The Hayes manual is lame as for schematics.

I wired mine into the on/off for the radio....kinda shady, but i couldn't find the wire either. So if my radio is on the lights on, but if my radio is off, my tach light is off.

Thanks, I hadn't thought of that, but I am leaning toward installing an audio pot under the dash and using that to adjust the brightness.
Will let you know how it comes out.

hey i wired my tach lite to my heater selector swict was kind of a pain puling it out but it works as soon as my lights are turned on.