Dome light WTH?

[firefighterwhite89]

Well, I purchased one of these-----> US SHIP New T10 W5W 168 48SMD LED Light Panel Bulb 3528 BA9S Dome Side Wedge Car | eBay and it works great. Not as bright as i thought it'd be, but none-the-less, it works...ONLY problem i have with it, is...Everytime i turn the light ON, my radio turns OFF. When i turn the light OFF, the radio comes back ON. WTF causes this?

On a side note, my stock Dome 31mm Festoon Light works perfect, and when turned ON, the radio stays ON. Completely the opposite of the LEDs...Any Ideas?

[rc00netzero]

OK That is seriously weird. How about some more details to go on like:
Engine Running Y/N/Both?
Stock or Aftermarket Radio?
Does the radio turn fully off or just quit playing?
Does it happen on door open, or just with the switch?
or any other details...

Typically this sort of behavior in a 12 volt system indicates a bad ground - but I would expect the behavior to be the same for LED and stock bulb in that case...

[firefighterwhite89]

Does have aftermarket radio. Does it with car on or off, door open or closed. Radio loses all power when Led bulb is in dome light receptacle on. When the stock bulb is in, the radio doesn't shut off when the dome light is on.


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[Dr_Snooz]

I'd recommend sticking as close to a stock configuration as possible when doing LEDs. That LED might be putting enough noise into the circuit to spook your stereo into some kind of protection mode.

I know I'm always tempted by the unbelievably cheap electronics on eBay, but it never turns out well for me. I'd say stick with a reputable retailer who sells LEDs designed for older car applications, like superbrightleds.com. Their stuff is all plug and play and I've never had a bit of trouble with it (beyond it not fitting well in the light housings).

[firefighterwhite89]

I bought another LED festoon light just like the stock one. Still the same thing happened. What all is the power wire connected to that runs to the dome light? Ironically, my radio is actually powered by its own wire ran from the battery. So I really don't understand why it would do this.
On a side note, my door lights never turn on when the dome light is set in the middle to that setting, but idk if that is really a factor. Maybe its a ground issue?

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[Dr_Snooz]

I'm more inclined to think it's your LEDs. You're using some veeery unconventional stuff. Even a relatively small change in the load on a circuit can cause a lot of extremely interesting things to happen. I'd sit down with a multimeter and make sure the voltages and resistances are still relatively within the right range. If, by some chance, you're running 17 volts to the deck on any of the wires connected to it, it's going to frowny face land. The stuff you're using isn't going to be plug-and-play. It's going to be plug-and-scratch-your-head-and-curse-and-tinker-and-tinker-and-tinker-and-tinker-some-more-and-play.

Another possibility is that you shorted something out while playing with the wires and released the magic smoke from some important electronic box somewhere. Now it's returning the favor.

Good luck with that. I fricking hate wiring.

[firefighterwhite89]

I'm going to delve deeper into this subject and find all the grounds and check connections. I'm finally starting my weekend in 30 minutes. Got a list of stuff to do.

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[firefighterwhite89]

I Figured it out guys.
I feel accomplished as at the same time, I feel like an idiot. Forgot that I had installed the now ridiculously expensive Smart-Glow Fuses(A red LED lights up when the fuse fails as an indicator), and having left the ignition on while checking fluids, i just happened to take off the fuse box and BOOM! Red LED on a 20A fuse in the number 13 spot. Replaced that fuse and OMFG, the LED dome light i switched to is like a street lamp along with my Trunk light. AND the radio no longer shuts off when i turn the dome light on.

Still got 3 questions yet to be answered though:

1. How was the lights getting power originally? If the fuse was blown, i could MAYBE understand why the LEDs would still light, though not as bright as they're supposed to be but WTF would the Stock filament festoon light light up for with a blown fuse, none-the-less, why would any of it light up period with a blown fuse?

2. How come everything interior lights work EXCEPT my damn door lights? They haven't worked for almost a year, and i never really bothered with it til recently. Would one blown bulb cause all to not to want to light up in the doors?

3. When i install the door lights as LEDs, what should i use for the Number 13 fuse? I was thinking maybe a 5A at max?(Literally, at that point, EVERYTHING will be ALL LED converted except the headlights, and they have their own fuse...)

[Hazwan]

That fancy LED fuse thing must have let the current to flow through it and would let your dome light/stereo to power up and would stop working intermittently once either stereo or dome light is switched on, drawing more power than the now LED 'fuse' allows it to flow.

Hows your door switches? Does the door indicator on the cluster work? They share the same fuse as the dome light/stereo if I'm not mistaken.

[Dr_Snooz]

I've always wondered why dead circuits often manage to register a few 1/10ths of a volt on a standard multimeter. I've always assumed it was some kind of feedback through the ground. Would that be enough to power an LED at a feeble output? For the door lights, you'll just have to troubleshoot it. It's not fun doing wiring troubleshooting, but it's the way to fix your problem.

[firefighterwhite89]

I've always wondered why dead circuits often manage to register a few 1/10ths of a volt on a standard multimeter. I've always assumed it was some kind of feedback through the ground. Would that be enough to power an LED at a feeble output? For the door lights, you'll just have to troubleshoot it. It's not fun doing wiring troubleshooting, but it's the way to fix your problem.

True. And in all reality, LEDs only need 1 volt to light up. 3 volts to shine to their full brightness. I guess i'll have to do some wiring troubleshooting. I gotta replace my damn CV Axle again this Monday, then I'll look closer into the wiring/interior door lights.

That fancy LED fuse thing must have let the current to flow through it and would let your dome light/stereo to power up and would stop working intermittently once either stereo or dome light is switched on, drawing more power than the now LED 'fuse' allows it to flow.

Hows your door switches? Does the door indicator on the cluster work? They share the same fuse as the dome light/stereo if I'm not mistaken.

I'm assuming the LED fuses use the circuit as a circuit when the fuse blows, and both having been LED, i guess that's how it lit up the interior dome light AND trunk light even with a completely blown fuse. I guess it still completes the circuit even though it's blown so it can light up the LED in the fuse itself...


My door switches all appear to be functioning correctly, none stick when you open your door. They're just as free moving as they used to be new. The Door Indicator on the gauge cluster DOES work...to a point. It only will indicate when my trunk is open. None of the doors OR hood are indicated when their open, but it will light up for the trunk EVERYTIME without failure. I believe you are correct though sir. The number 13 fuse as i recall DOES go to the Dome light/Door lights/Trunk light/Safety indicators etc.
As i'm looking at the wiring manual, I know the White/Blue wire has power because the Dome light lights up correctly, BUT, only lights when in the ON position, It won't light in the DOOR position when any doors are open. I'm willing to guess it's a Ground issue.
I'll check for voltage at the lighting terminals itself on each door. I've got this fused power checker thing that looks like a screwdriver and lights up the handle if whatever you're testing has power. I'll test the sockets with the bulbs in and doors open and see if i can get power. If so, the grounds need to be fixed. If not, I'll know it's the power wire either leading from the dome light or a short in the wire somewhere.

[Hazwan]

Both door indicator light on the dash and the door position on the dome light are grounded through the switch and the contacts on the switches are known to corrode so I would start from there. Better yet, take the switch out and ground the wire directly on somewhere and see if it lights up. If thats the case then clean up the contacts.

[firefighterwhite89]

Both door indicator light on the dash and the door position on the dome light are grounded through the switch and the contacts on the switches are known to corrode so I would start from there. Better yet, take the switch out and ground the wire directly on somewhere and see if it lights up. If thats the case then clean up the contacts.

Thank you very much. You've got an excellent point. Only two places i've ever seen corrosion on this 86' is on the back of the gauge cluster itself and the dome light. I'd bet it's corroded again. My sunroof leaks at random when it rains for long periods of time and when it does, it fills the area the sunroof slides away into...which just happens to be exactly where the dome light is attatched.

[Hazwan]

I mean the door switches