Unusual radio issue

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Matt69olds

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My son and I installed a Retro Sound stereo in his 92 Yukon about 6 months ago. When we first installed it, we had trouble with the radio not shutting off. I have had lots of experience with things NOT working, not do much things that won’t stop working! I checked for power on the red wire (ignition power feed) and it cycles off/on with the key as expected.

Based on that, I ASSUMED the radio was defective. RetroSound agreed and sent an exchange radio. For the most part, that solved the problem. Occasionally, the radio would continue to play with the ignition off.

Now, the problem is constant. Time to dig into and solve the issue. With a test light, once again power turns on/off with the key. However, when the radio is PLAYING with the key off, as soon as you touch the test light to the red wire, the radio IMMEDIATELY shuts off. Hmmm!!!

I then used a digital voltmeter to actually measure the voltage on the red wire. With the ignition on, it measures battery voltage. When you shut off the ignition, voltage immediately drops to around 11 volts, and slowly trickles down to around 9 volts. Clearly, 11 volts on that wire is enough to cause the radio to think the ignition is still on. Obviously, there is leaky voltage on the radio feed wire. Pulling the radio fuse immediately removed the parasitic voltage.

My question: what else is on the radio circuit that could be causing voltage to bleed enough power to keep the radio on? Other than a brake controller and electric chromatic rear mirror with compass/temp, there is nothing aftermarket on the truck. Nothing has been cut or hacked up.

Anyone in readerland have any ideas?
 

Jgonick

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I put a retro sound in my truck a few months ago. First day, same thing happened as you- radio stayed on with key off. Hasn't happened since though...
Be interested in what you find...


Update- Now you got me thinking about this. Since it hadn't happened since (& only once) I didn't give it much thought since then. As you know, when you turn the car off the radio display takes a few seconds to shut down. It was late in the day & I remember thinking it had gotten stuck shutting down and ended up yanking the fuse. I was going to look at it the following day, but I couldn't get it to do it again. Very Odd
 
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Matt69olds

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I put a retro sound in my truck a few months ago. First day, same thing happened as you- radio stayed on with key off. Hasn't happened since though...
Be interested in what you find...


Update- Now you got me thinking about this. Since it hadn't happened since (& only once) I didn't give it much thought since then. As you know, when you turn the car off the radio display takes a few seconds to shut down. It was late in the day & I remember thinking it had gotten stuck shutting down and ended up yanking the fuse. I was going to look at it the following day, but I couldn't get it to do it again. Very Odd
We noticed the radio continues to play for several seconds after shutting off the ignition. I thought it was strange, now that I know about the residual voltage on the radio circuit does it make sense the radio keeps playing BECAUSE of the voltage on that line, it takes a few seconds for the voltage to drop low enough to shut off.
 

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Crutchfield supplies a OE plug adapter utilizing the OE harness, just wondering if that was used or self wired, shouldn’t make a difference, just wondering
 

Jgonick

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I just assumed it was a small capacitor in the radio that gave the few seconds of power while shutting down. I know very little about radios though.
My initial thought is it is something wrong with the radio- I keep thinking about how the radio has two 12volt wires going to it and if the battery one is back feeding to the accessory one somehow - but that doesn’t really make sense either. Yanking the radio (accessory) fuse kills it.
 

Turbo4whl

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Thinking about this for a day, here is what might happen. In my 2006 GMT800, when you turn off the key, the radio stays on until you open the door. Many newer vehicles are that way. If you don't open the door, the radio will turn off after 5 or 10 minutes.

So a newer radio, like a Retro Sound may have that feature. In the aftermarket radio wiring diagram, does the radio have a wire that is supposed to connect to the door dome light?
 

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After I finished the re-wiring of the '73 Bronco, brother-in-law had someone else install a RetroSound radio. And then Weird Things began to happen. The instrument panel lights stayed on anytime the key was on and they were VERY BRIGHT. The parking/running lights were on all around but they were dim.

My troubleshooting led me to the factory radio light wire. The light in the factory radio is connected to the instrument panel lights and it brightens/dims with the instrument panel lights by rotating the light switch. Our friend did not know what to do with that "extra" wire so he just wired it into the power wire feeding the radio. That put full voltage to the wrong side of the rheostat that controlled the brightness of the instrument panel lights. It also back fed the parking/running lights.

The RetroSound does not use that wire from the instrument panel lights, that may not be your problem but it gives you something else to look at.

@Turbo4whl that feature is usually controlled using the power going to the radio, not something within the radio itself. The RetroSound and Custom Auto Sound radios I have dealt with did not have that capability within themselves. They may offer that feature...I just have not seen it on the few I worked with/on.
 

Jgonick

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@Turbo4whl I can only speak for mine, but Retro has two 12v wires running to the radio for power. On my 85 k10 - One is the original yellow wire running to the fuse box (Radio fuse) -Retro changes it to red. This is the accessory power. The other wire is spliced to the cigarette lighter feed (orange)- Retro changes it to yellow. This is the battery feed for the memory (it has an inline fuse). This was spliced by a PO for an old aftermarket radio. It was/is very common to splice it at the cigarette feed for constant power.

Just to remind everyone. Mine has currently stayed on only once and has not happened again-Yet. Unlike Matt69olds which is happening all the time.

Logic would tell me it is the ignition switch allowing occasional bleed through to the accessory circuit. I really don't see much else it could come from on my truck.

@Matt69olds - What makes me shy away from the ignition switch and focus more on the radio is that your problem disappeared for a while when you changed radios. Why? you didn't correct the problem other than new radio. The problem is getting worse so I would assume something is failing more frequently or completely by now.

I googled and came up with a couple of threads about this issue. Really no reason why or solution was ever mentioned.- But it did confirm a few others have had this problem and it did tend to start happening more frequently.

@Redfish My instrument panel light wire is not hooked up. But that is very interesting.
 
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Jgonick

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My initial thought is it is something wrong with the radio- I keep thinking about how the radio has two 12volt wires going to it and if the battery one is back feeding to the accessory one somehow - but that doesn’t really make sense either. Yanking the radio (accessory) fuse kills it.
Just thinking out loud... The radio itself- Could the battery power wire be using the accessory power wire as a potential weak ground when the car is off? Pulling the fuse or touching it would disrupt it. Meaning it's a radio defect and/or a better ground would possibly take care of the problem??.
 
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Matt69olds

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Well, I tried anew ignition switch today. Didn’t fix a damn thing.

As someone mentioned, the factory wire color for ignition feed to the radio is yellow, it changes to red for the aftermarket radio. Orange is the factory wire color for constant power, it changes to yellow for the new radio.

I did find a chart that showed power distribution, the radio, wipers,and connivence center all share the same buss bar for power to the fuses. Only the radio fuse shows the residual voltage.

I think my next move will be to pull the firewall connector and connivence center panels. Maybe I’ll find some corrosion, or some other reason for errant voltage on the radio circuit.

I’m really scratching my head on this one.
 

Matt69olds

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Crutchfield supplies a OE plug adapter utilizing the OE harness, just wondering if that was used or self wired, shouldn’t make a difference, just wondering

Yep, we ordered the radio thru Crutchfield.

While they still SELL the retro sound brand, they no longer offer tech support for them.
 

Jgonick

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@Matt69olds Do you think its back feeding through the radio - like a bad diode or something? What happens if you pull the inline fuse out of the yellow wire (battery feed for memory) Just to test it- that way the radio is getting no power at all once it is switched off.
 

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Well, I tried anew ignition switch today. Didn’t fix a damn thing.

As someone mentioned, the factory wire color for ignition feed to the radio is yellow, it changes to red for the aftermarket radio. Orange is the factory wire color for constant power, it changes to yellow for the new radio.

I did find a chart that showed power distribution, the radio, wipers,and connivence center all share the same buss bar for power to the fuses. Only the radio fuse shows the residual voltage.

I think my next move will be to pull the firewall connector and connivence center panels. Maybe I’ll find some corrosion, or some other reason for errant voltage on the radio circuit.

I’m really scratching my head on this one.
Matt, it's been a loooong time since I've done any automotive custom sound installations so I have very little experience with today's systems. You may have already considered this suggestion.. Disconnect all power providing wires/sources to the radio. Attach a volt meter to the ignition hot wire to the radio and start the engine. Check to be sure you have voltage on that wire. Turn the engine off and observe how long it takes for the voltage to bleed down. If it takes a while, the problem is in your vehicle.. If the voltage bleeds rapidly, the source of the problem is the radio..
 

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