2ndhandyotaman
Member
Hello guys and gals, I'm finally at the point of being able to try to fix little annoyances, one of the biggest is the non functioning backlights on the stock stereo. I did a search and found quite a few threads about this, so it's pretty common but I haven't seen a thread of what exactly the fix is. Mine has an external amplification device plugged into it, if that makes any difference.
I removed the stereo and opened it up to have a look inside. . The PC board behind the dials has a metric boatload of surface mount LEDs. I reasoned that there's no way that (1) everything was wired in series, and (2) there's no way ALL of them are burned out so I looked at the traces ( pathways) and found a few common points, so I grabbed a 9V battery, some short test leads and an un-decoded resistor that I had in my LED build bag so that I could drop the voltage.
After a few minutes I found a sweet spot [ I'll keep this PG-13 !] and got this:
They're all lit up ! This at least verifies that they aren't burned out. I thought that maybe it was a loose connector from the harness, so I put the deck back together and put it back into the 'Yota. I turns on the key, clicks the headlight stalk and got- nada.
Hmm, now what. I don't think it's worth putting too much time into this but I'll go a bit deeper. I'm guessing that somewhere in the main plug in the back that one of those wires has to be a signal from the dash lights to turn on the stereo lights. Does anyone have a diagram of the pin out for the plug? I'll go as far to see if there's a voltage signal at the harness when the lights get switched on. If I find a signal there, then the issue is buried somewhere within the confines of a 17 year old AC Delco deck. (Yup, that what the decal on the side said- the vendor was AC Delco, whom is nothing more than a 'reboxer' so the deck could have been built by virtually anyone at all, we'll never know fer sure.)
If I don't get a signal at the harness, it might be worth a bit more probing to figure out where the signal should originate from, at least it won't cost anything to dig around in the wiring harness. And if I go to a snazzy double din blue toof enabled touchy screen device, I'd probably need that light switch signal to function anyway.
I removed the stereo and opened it up to have a look inside. . The PC board behind the dials has a metric boatload of surface mount LEDs. I reasoned that there's no way that (1) everything was wired in series, and (2) there's no way ALL of them are burned out so I looked at the traces ( pathways) and found a few common points, so I grabbed a 9V battery, some short test leads and an un-decoded resistor that I had in my LED build bag so that I could drop the voltage.
After a few minutes I found a sweet spot [ I'll keep this PG-13 !] and got this:
They're all lit up ! This at least verifies that they aren't burned out. I thought that maybe it was a loose connector from the harness, so I put the deck back together and put it back into the 'Yota. I turns on the key, clicks the headlight stalk and got- nada.
Hmm, now what. I don't think it's worth putting too much time into this but I'll go a bit deeper. I'm guessing that somewhere in the main plug in the back that one of those wires has to be a signal from the dash lights to turn on the stereo lights. Does anyone have a diagram of the pin out for the plug? I'll go as far to see if there's a voltage signal at the harness when the lights get switched on. If I find a signal there, then the issue is buried somewhere within the confines of a 17 year old AC Delco deck. (Yup, that what the decal on the side said- the vendor was AC Delco, whom is nothing more than a 'reboxer' so the deck could have been built by virtually anyone at all, we'll never know fer sure.)
If I don't get a signal at the harness, it might be worth a bit more probing to figure out where the signal should originate from, at least it won't cost anything to dig around in the wiring harness. And if I go to a snazzy double din blue toof enabled touchy screen device, I'd probably need that light switch signal to function anyway.
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