What is "lights on signal" wire to the radio?

[Frank]

I'm replacing the headunit and this wire called "lights on signal" from the
dash radio wire harness to be connected to one of the terminals on the new
radio wire harness. There is no corresponding "lights on signal" terminal on
the new radio wire harness. What does the "lights on signal" do and where
should it be connected? Could it be connected to the "+12V ignition" wire to
the radio?

 

[Walt Kienzle]

Many aftermarket headunits don't require the signal to adjust the panel
light brightness. Factory radios use this when the headlights are switched
on, therefore it is a "[head]lights on signal". Just cover it with
insulating tape; don't connect it to anything. If you do, you will likely
blow fuses or cause other problems.

 

[Frank]

Many aftermarket headunits don't require the signal to adjust the panel
light brightness. Factory radios use this when the headlights are
switched on, therefore it is a "[head]lights on signal". Just cover it
with insulating tape; don't connect it to anything. If you do, you will
likely blow fuses or cause other problems.

Bingo, thanks Walt!

 

[Roland Messerschmidt]

Many aftermarket headunits don't require the signal

....but many other do use this signal anyway.

It's not only a (digital) on/off signal, but a signal to dim the radio
display with the dashboard lights.



Roland