joe.smith Posted October 4, 2015 Report Share Posted October 4, 2015 I just installed the AppRadio 4 in my 2004 GMC Sierra 1500 and was twisting my brain out trying to figure out why my backlit display brightens when the parking/head lights are on, and dims when parking/head lights are out. This is the opposite of what should happen. After pulling out my voltmeter and checking the factory wiring manual, I finally realized my vehicle 'grounds' the parking lights wire to turn them on (obviously to engage the relay in the engine compartment). It appears the AppRadio 4 expects there to be 12VDC on the illumination line when the lights are on. Has anyone else encountered this? I've looked and looked, but there just aren't any other lines I could tap into within the cabin which reflect the status of the parking lights. As I don't want to run wires through my firewall to the engine bay, is there a way to configure the AppRadio 4 so a ground on the illumination wire tells it the lights are on? Thanks for any help, Joe Quote Link to post Share on other sites
fruitbat04 Posted October 4, 2015 Report Share Posted October 4, 2015 Does it matter? I could be wrong but I think all the brightness settings are configurable on each profile. Quote Link to post Share on other sites
joe.smith Posted October 5, 2015 Author Report Share Posted October 5, 2015 Does it matter? I could be wrong but I think all the brightness settings are configurable on each profile. Does it matter? Are you asking "does it matter" that I don't want a bright screen shinning in my face at night? Maybe you're asking, "does it matter" that I don't want a dim one I can't see in the daytime. Or, are you asking "does it matter" because I can just set both day/night modes to the same brightness level, essentially negating a feature of the radio? To that end, what level should I set the brightness? Really bright all the time or really dark, or at an unsatisfactory level for both day and night? Or maybe I can just adjust the brightness level every time I get into my vehicle. "Does it matter?" YES, it most certainly does matter. What a snarky respone. You know, it's okay to NOT post a reply if you don't actually have an answer to my question... Joe Quote Link to post Share on other sites
fruitbat04 Posted October 5, 2015 Report Share Posted October 5, 2015 Sorry, you've taken my reply the wrong way. What I mean is that I think the settings for for brightness on the screens are set on 2 profiles, one which always activates when the lights are on and one one they are off. So it "Doesn't Matter" if you've got them inverted, because you can set all the levels to exactly as you want on each profile. Try setting the levels as you want with the lights turned on. I think it will retain them. Quote Link to post Share on other sites
fruitbat04 Posted October 5, 2015 Report Share Posted October 5, 2015 In fact, if you check page 84 of the English manual, it says that the Brightness and Contrast settings are stored independently with the headlights off and on. Quote Link to post Share on other sites
fruitbat04 Posted October 5, 2015 Report Share Posted October 5, 2015 The other option is just wire in an NPN transistor to invert the signal Quote Link to post Share on other sites
joe.smith Posted October 5, 2015 Author Report Share Posted October 5, 2015 My apologies for taking it the wrong way. That's the problem with the Internet - you lose a sense of someone's tone/intent with the words. Anyway, I now understand your statement. Yes, there are different profile settings for day/night brightness levels. My user manual for the AppRadio 4 states explicitly, however, that the brightness level will automatically change only if the 'night' brightness level is below the 'day' level. So, I couldn't get that work-a-round working. Incidentally, I talked to Pioneer Tech Support today and they confirmed that illumination polarity is not a user configurable item. I suggested they allow that in their next firmware update because I can't be the only GM owner to run into this. He said he would forward it up. Does anyone know of another parking signal wire I can tap into? I read somewhere that there is a POSITIVE parking light signal at the driver's side fuse kick panel, but I can't check that out until I get home. Joe Quote Link to post Share on other sites
joe.smith Posted October 5, 2015 Author Report Share Posted October 5, 2015 The other option is just wire in an NPN transistor to invert the signal That's what I was thinking about doing, only I was going to use a general purpose relay to do it. A solid state device would be a more reliable choice, long term, though... Joe Quote Link to post Share on other sites
joe.smith Posted October 5, 2015 Author Report Share Posted October 5, 2015 The other option is just wire in an NPN transistor to invert the signal It would be a PNP transistor, though, right? Joe Quote Link to post Share on other sites
fruitbat04 Posted October 5, 2015 Report Share Posted October 5, 2015 Yes sorry PNP. As its only switching and no current will flow, you could get away without any perfboard and just solder it directly the leads to the legs and heat shrink. A relay would possibly be more reliable but without any real load, any transistor should last a lot longer than the life of the unit. Quote Link to post Share on other sites
joe.smith Posted October 8, 2015 Author Report Share Posted October 8, 2015 I just wanted to close the loop on this thread and archive the solution: I finally found a positive parking voltage I could tap into within the passenger compartment. It's on the Relay Block I/P, which is located by the driver's kick panel. You can find the necessary signal on C10 or D10 of the connector block. Joe Quote Link to post Share on other sites
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