Posted by: Bernz
Headlight sense night dimming problem (voltage too low?) - 08/06/2006 03:20
My headlights-on voltage is around +11V. The sense line for night dimming is listed at +12V to activate. Night dimming does not work for me. Am I right to suspect that the voltage is not quite high enough to activate the sensor?
At some point, I am probably going to wire something up to work around this (opto-coupler gating constant-power to headlight sense wire, controlled by car's headlight voltage), but in the mean time, can anyone confirm/refute this interpretation of the problem?
Posted by: tfabris
Re: Headlight sense night dimming problem (voltage too low?) - 08/06/2006 03:22
I can't imagine it would be THAT picky. Just to be sure, you already checked
all this, right?
Posted by: Bernz
Re: Headlight sense night dimming problem (voltage too low?) - 08/06/2006 03:27
Wow, awesome response time! Actually, although I'd read a good deal of the FAQ, I hadn't yet got to the dimmer-related stuff, and I hadn't thought to check there yet. So, I will definitely go over all that stuff first. Thanks for the tip!
Posted by: Shonky
Re: Headlight sense night dimming problem (voltage too low?) - 12/06/2006 01:07
Is it 11V DC though? Some newer cars (e.g. VW) have a PWM signal for dimmer since the signal passed to the stereo is more than just on off. i.e. the dash brightness control also controls the brightness of the factory stereo's backlighting. The empeg doesn't have this. It simply has an on/off setting.
If you've measured it with a multimeter on DC a switching signal it could quite rightly measure 11V. A poor man's check for a switching signal is to put the multimeter on AC volts. If it reads non-zero then it's likely it's a pulsing signal.
Posted by: tfabris
Re: Headlight sense night dimming problem (voltage too low?) - 12/06/2006 01:10
The empeg should properly handle a PWM signal, though. And I'm still pretty sure that it'd stil work with 11v.
Posted by: Shonky
Re: Headlight sense night dimming problem (voltage too low?) - 12/06/2006 01:31
I think I know what the problem might be. The empeg has no definition of dimmer line active or not really. Rather it just stores two seperate dimmer settings for each state of the dimmer line. I would guess you have both set to 100% so it appears the dimmer isn't working.
You need to adjust the dimmer from the menu, while the dimmer line is actually active.
Just realised that that's what Tony linked to in the FAQ. Thought I'd post it anyway.
Posted by: drakino
Re: Headlight sense night dimming problem (voltage too low?) - 13/06/2006 13:48
I'd have to double check my wiring, but I believe my empeg is hooked up to a PWM signal for the sensing, as the stock stereo paid attention to that line as a dimmer indicator along with the rest of the dash. The installer may have found a solid 12v line though in the dash and used it, it's been a couple years since I saw the spagetti mess of wiring.
Posted by: altman
Re: Headlight sense night dimming problem (voltage too low?) - 20/06/2006 19:02
ISTR it does handle a PWM signal; the player software requires no high levels on the line for a certain time (a second? half a second?) to decide it's actually low.
Hugo