Lost all radio illumination

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Hey y'all, I am having some issues with the illumination in my radio. This is in a 1995 K1500 Silverado, it's a junkyard pull radio but it worked great. I just replaced the burnt out stock bulbs with Leads and plugged it in, it worked great. I then did the 2 bulbs in the CD player, got a small wisp of smoke and now none of the radio lights work. Radio still plays, just no lights and no blown fuses.

The bulbs included resistors for 12v power so I know that isn't the issue. I thought maybe I wired them wrong in the CD player only, I tested the radio ones before doing the CD player and they all worked. Is there an internal fuse to the radio lights or something that I am missing? They won't even come on with the CD player disconnected.
 

454cid

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If you saw smoke, I'd guess you blew something more important than a fuse. Sorry, I can't be more of a help. My radio has issues too... the lights constantly bounce back and forth between day time and night time brightness.
 

GMCTruck

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Check fuse 14.
Perhaps you forgot to trim a lead or you bridged between two leads of a bulb and created a short. If the fuse 14 is blown, you will have to closely inspect the bulbs in the CDP.
 
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I took the CD player and radio faceplates back off and on the face circuit boards, I see no burns or obviously blown components. With a 9v battery I can light up all the lights at once, touching the battery terminals to any lightbulb with a short lead will light them all, i.e. the illum circuit is intact at the faceplate. Digging deeper.
 

F4U-1A

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Nothing wrong with Digging, do it here every G Damn winter (I am a
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Okay, I have the whole radio torn open. I am not an electrician, not even close. But the things I feel like I should be looking for, such as scorching, ruptured little components, melted wires and the like, are all absent. It all looks perfectly healthy inside. My clock screen still lights up, as long as the dash lights are off. Dash lights on, clock screen dies and no illumination. Still plays audio. I am stumped.

Oh, and just to be sure, I checked fuse 14. Not blown.
 
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As an added update, all other functions of both the radio and the CD player are operational. If I can't figure it out, I'll hit up the junkyard and try again with a new set, I guess.
 

GMCTruck

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I have never worked with LEDs in a vehicle but I know that LED lights only work in one direction. That is, being a diode, current only flows one way through it. When you say that you changed the bulbs in the radio and then tested it and it worked, how did you test it? Did you plug it into the truck wiring or did you connect a battery on the bench? If you installed all the bulbs backwards, then a battery will still light them up depending on the orientation of the battery + and -. Turn the battery around and nothing will light up.
 
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I tested the lights as installed by plugging the radio into the truck and turning on the dash lights. Before messing with the CD player, all 10 LEDs in the radio faceplate lit up just fine.
 

GoToGuy

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So headlights off radio illumination on. Headlights switched on no radio illumination. That switching is done internally in audio units. The dash lighting signal or power circuit swtches internally to headlight switch dimming control. This is why we disconnect power/ battery before touching things.
 
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