I am loving the new kiv-bt901 I installed. GREAT little single din media unit (no cd or dvd built in) which I highly recommend to those of us who decide double din is not the answer.

(And really, having owned fixed and flip-up screens.. unless you turn them off, due to their relatively large size they put out a lot of light at night)

But there is the issue. I wired up the illumination wire on the hu to the HVAC unit. This works perfectly as it should. However, if I dial the interior lights to be OFF at night the hu's screen pops back to the daytime setting. So it works as you would expect from the hvac illumination feed.

---> What is the closest connection I can utilize which will set the hu's illumination to be dim whenever the headlight toggle is anywhere but off?

 

I'm not sure if what you're looking for exists as you described it. That doesn't mean it's not there somewhere, I just don't know of it off hand.

You could rig up a 5v regulator (I believe that's what the dimmer circuit runs at) that is connected to the headlight wires under the steering column, then run that 5v output to your HU dimmer wire. That would dim the unit whenever the headlights are on regardless of any interior lights settings.

To take that one step further....
You could use both the current dimmable setup AND what I described above at the same time if you use a 5v coil DPDT relay. Use current dimmer circuit on the coil, then connect the dimmer wire you're using now to one set of N.O. contacts, and connect the 5v regulated headlight power to the other set of contacts on the N.C. pole. A few diodes to keep the two separate wouldn't hurt.

That would energize the relay and use the normal dimmer signal when it was on, but if you turn off the interior lights the relay coil would turn off causing the headlight 5v to be your dimmer circuit. If the headlights are on at that point the unit will dim, if headlights are off it will be in daytime mode.

 

Snag a parking light wire under the dash would mean radio is bright until you turn parking / headlights on

 

Mark - you are to wiring what I am to computers. I always enjoy a guy not afraid to lay out the extra options!

Penta - I'll have to see what is where.

It ought to be easy enough, since I'll have the dash and cluster out to install HUD and new gauge faces.

I'll search for a wiring diagram to tell me what wires I need to find. It seems the key is regulating to 5v from 12v.

 

Where is the 5 volts coming from?

 

"You could rig up a 5v regulator (I believe that's what the dimmer circuit runs at) that is connected to the headlight wires under the steering column, then run that 5v output to your HU dimmer wire. That would dim the unit whenever the headlights are on regardless of any interior lights settings." - from MarkCZ

That's where I got the 5v reference.

I'll bet there is a wire involved with the lights via the column stalk which would do the trick, too. Just need to find a wiring diagram.

 

IMO brown at headlight switch is what you want which is signal for parking lights

 

If Greg says the brown wire works, I'd bet it does