Overriding dashboard headlight illumination/dimming of aftermarket stereo

[epjfsa]

I did plenty of searching and probably found enough relevant info to go about this on my own, but first wanted to see if anyone has done something similar.

The problem is that aftermarket stereos with only one dim/illumination wire will dim depending on the state of the headlight switch, but not of the dash dimmer wheel to the left of the steering wheel. I drive with my headlights on 100% of the time, and because the stereo doesn't respond to the dimmer wheel's override (clicking it into the top position), I have to manually change the stereo's dim on/off through nested menus depending on the time of day.

One solution I've considered is to somehow tap into the factory dimmer switch to control a relay (or more likely a PNP transistor). I'm thinking this would go in-line with the orange dimmer wire and would open the circuit when the dimmer wheel is clicked into the top position. Any thoughts or suggestions?

 

[jhguth]

Is it just a 12v signal? Just wire a switch for the dimmer input to a whatever voltage source you need and use it to manually dim your stereo

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[jdm-v35]

The OEM stereo dims based on variable voltage through that one wire with all the other accessory lights. It depends on your aftermarket stereo. I think most are just triggered by either voltage on/off on that dimmer wire because most people do not change it throughout the day.

the voltage already varies, so it is just how your aftermarket stereo works most likely.

What you propose doing will not make any difference as it is just a function of the stereo you bought.

 

[epjfsa]

Is it just a 12v signal? Just wire a switch for the dimmer input to a whatever voltage source you need and use it to manually dim your stereo

Sent from my SM-G930V using Tapatalk

That is, of course, the easy way to do this -- but I don't want to deal with flipping two switches if I can do one. Even better would have been Toyota implementing an incredibly simple circuit to auto-dim the dash and cluster lights. Even my '97 M3 had this:shrug:

The OEM stereo dims based on variable voltage through that one wire with all the other accessory lights. It depends on your aftermarket stereo. I think most are just triggered by either voltage on/off on that dimmer wire because most people do not change it throughout the day.

the voltage already varies, so it is just how your aftermarket stereo works most likely.

What you propose doing will not make any difference as it is just a function of the stereo you bought.

Sorry, my post may not have been clear. I understand why it's happening, so I'm trying to override what you described which is to block the 12v signal to the stereo that triggers dimming. The idea is that when the factory dimmer wheel is clicked into the highest position, a relay would open the dimmer circuit to the stereo. I just wanted to first check to see if anyone had done something similar or is at least familiar with tapping into the factory dimmer switch before I head out with my multimeter

 

[jdm-v35]

If you want to block the dimming signal, just disconnect the orange wire that controls dimming from the plug.

If you are trying to just have the dimming feature on all the time, just splice the stereo dimming wire into your remote turn on wire.

 

[jhguth]

That is, of course, the easy way to do this -- but I don't want to deal with flipping two switches if I can do one. Even better would have been Toyota implementing an incredibly simple circuit to auto-dim the dash and cluster lights. Even my '97 M3 had this:shrug:



Sorry, my post may not have been clear. I understand why it's happening, so I'm trying to override what you described which is to block the 12v signal to the stereo that triggers dimming. The idea is that when the factory dimmer wheel is clicked into the highest position, a relay would open the dimmer circuit to the stereo. I just wanted to first check to see if anyone had done something similar or is at least familiar with tapping into the factory dimmer switch before I head out with my multimeter

If you want it automatic just wire a basic light sensor to the source, shouldn't cost you more than a few bucks for all the supplies you need

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