Unusual radio issue

[Matt69olds]

The radio and amps are completely unplugged. The tiny amount of voltage is still there, it’s not coming from the radio.

 

[Jgonick]

Crud - I really thought it was going to be the radio..

Since I don't know how you disconnected the radio, I'll mention my next idea. Did you check the connectors. The red & yellow wires are next to each other. If they were touching that would allow constant power to bleed over to accessory. - Just a long shot.

 

[Copymutt]

Some if us are so old we don’t recall particulars. But, the thing that popped into my head was an alternator issue causing this. Bad blocking diode and battery is feeding the radio thru charging circuit. Next time the radio stays on unplug the alt. See if that kills the radio.

 

[RanchWelder]

I see Zener Diode's and resistors, installed on all your switches and relay circuits, in your future...
What do I know?

Search my post for Fly-Back isolation or search the internet.
Most of the links you find on your first page of results, will waste your time. You'll need to deep dive.
3-4 hours of searches, is what will bring you the actual way to isolate fly-back.

Idiots making bad things get censored from the search engines, so I hope you do not pop up on the radar, as one of them...
Everything matters, all the time.

Fly-Back is no joke. Buying the parts, is no joke. Activating an account at an electrical engineering supply company, is no joke.
Your underwear had better be very clean.

That capacitor, required for overloading the electrical system, had better be a quality unit within 4 years of manufacturing, or it will kill your system.

A 1 micro-farad cap is only rated for 2-3 years of use. It is a disposable item and requires excellent ground fault protection.

Installing audio systems into a vehicle is high science. Learn or get screwed by a shop with bad manners.

When you burn up the diode in the cluster, installing a radio with high power amp and cap, you'll create a volatge drain in the cluster which you you cannot repair. It will kill your battery. every day you charge, it will die in three days, untill you replace the damaged cluster.

It's only $350 plus shipping plus a core charge for a repaired cluster from R/A.

I wonder what they put in there?

 

[mtbadbob]

Back in the day when I was really into car audio, Pioneer was the only systems I would run. That being said, yellow wire was ALWAYS illumination. You'd hook it up to the headlight switch and the unit would illuminate when the lights were on, and also you could dim the unit with the instrument lighting, so the stereo wasn't obnoxiously bright.

 

[RanchWelder]

The problem is with the modern electrical system wiring from GM, anything you tap into the gauge or OEM Stereo wiring, (instead of home run to the battery with fuse); causes feedback through the ground system diodes and burns up the cluster diode.

Bet me.

 

[Andreas Wickman]

Interesting reading. I have the same problem with my Retro sound radio. Not every time but say once a week the radio display don't shut down, but there is no sound and you cant turn the radio off by pressing the left hand button. The only way is to pull the fuse. And if you don't, and the truck stands in the garage for say 3-4 days the battery is drain. So its really annoying.

 

[AuroraGirl]

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?

RAP
Retained Accessory Power

Showed up in the 90s in gm high end cars , filtered down over time to most models

 

[Matt69olds]

RAP
Retained Accessory Power

Showed up in the 90s in gm high end cars , filtered down over time to most models

Retained accessory power was still a few years away when this truck was built.

Been dealing with the flu, haven’t really had much motivation to dig deeper into this problem. Hopefully the weekend cooperates.

 

[AuroraGirl]

Retained accessory power was still a few years away when this truck was built.

Been dealing with the flu, haven’t really had much motivation to dig deeper into this problem. Hopefully the weekend cooperates.

be greatful they gave you the feature! just wish you knew how lol jk

 

[Matt69olds]

Great big steaming piles of horse excrement!!

Took apart and cleaned the bulkhead connector, didn’t see anything out of the ordinary. Tidied up some wiring under the dash, didn’t really change anything other than routing to make service easier.

Reassembled everything, and now everything works as expected.

Wonder for how long???

 

[Jgonick]

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

@Matt69olds My stupid radio stayed on again today- (it has been roughly 2 years since it did this to me only one time) had to pull the fuse-(going to the radio's constant 12v for memory) - waited a minute and put the fuse back in and all is working normally again. Did you ever figure out what was going on with yours son's ?

 

[AuroraGirl]

@Matt69olds My stupid radio stayed on again today- (it has been roughly 2 years since it did this to me only one time) had to pull the fuse-(going to the radio's constant 12v for memory) - waited a minute and put the fuse back in and all is working normally again. Did you ever figure out what was going on with yours son's ?

what is the "on" just a screen lit up or actual audio and stuff all working
Maybe internally has a circuit that allows Retained Accessory Power behavior but its malfunctioning

 

[AuroraGirl]

I didnt even read this thread again but its funny my suggestion last year was the thing i suggested is possible this year LOL.

The radio youre talking about is a aftermarket right, not OEM?

@Matt69olds My stupid radio stayed on again today- (it has been roughly 2 years since it did this to me only one time) had to pull the fuse-(going to the radio's constant 12v for memory) - waited a minute and put the fuse back in and all is working normally again. Did you ever figure out what was going on with yours son's ?

 

[AuroraGirl]

@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.

have you ever done your ignition switch push rod or the switch at all? these trucks wouldnt surprise me if there wasnt a fair amount of ghost voltage in the wiring from miliamp level shorts at things like bulb bases , cracked wires etc.
You could run put a small resistor on the wire for power , or put a light bulb in the line before it, to probably stop the thing if it was the cause

I pulling the harness wrap and separating the wires to check for insulation breaks might be wise too


Maybe the fuse panel itself has something going on, or your ground connection isnt constant/its switched