New head unit - now no dash lights

Last time I did this I ended up wiring the ground of the radio to the illumination lead on the car. When the lights are off the illumination lead looks like a ground, until you turn on your lights. Then it usually blows a fuse, which seems to short out the illumination lead to ground and keep the radio working. Pull the ground wire from the radio and ground it to some metal of the car or a known good ground wire and replace your fuse (which is probably blown). Allan

Last time I did this I ended up wiring the ground of the radio to the illumination lead on the car. When the lights are off the illumination lead looks like a ground, until you turn on your lights. Then it usually blows a fuse, which seems to short out the illumination lead to ground and keep the radio working. Pull the ground wire from the radio and ground it to some metal of the car or a known good ground wire and replace your fuse (which is probably blown). Theres an article in Crutchfields tech support site here: http://www.crutchfield.com/S-pd3XJdF5Bcj/tech/kb32.html that may be of some help Allan

what make and model of vehicle do you have.maybe you have to wire the illumination wire to your ignition wire

Thanks guys,  I did indeed have the illumination wire grounded and had blown the fuse.  sorted now and i can see how fast i am going at night  :)