LED dome and map lights issue.
LED dome and map lights issue. I tried doing a search but didn't find much so sorry if this is a repost. I replaced my Dome and map lights with LEDs. I noticed last night after they were all installed and once it became dark out that my lights are on all the time but very very faint. I decided to check the voltage and with everything off and doors closed it reads roughly 7 volts. If I turn the lights on it reads the normal 12v. Anyone know why I have a constant 7 volts going to my lights?
sounds like you've got a short somewhere. If you're proficient with a multimeter it's as simple as tracing your wires. It would be MUCH easier if you also know how to read a wiring diagram and have access to one. Possibly a defective dimmer switch, you just may not have noticed it with the regular bulbs installed. Good luck!
Theres enuff residule electricity in the wires in the lighting circuit when the ignition is on , even when everything is off , to power led's very dimmly ( 1 volt or less will light up very dim 
) . If you intend to stay with LED's , wire in a diode between the + and - wires so theres no backfeeding and that should solve your problem .
) . If you intend to stay with LED's , wire in a diode between the + and - wires so theres no backfeeding and that should solve your problem . sounds like you've got a short somewhere. If you're proficient with a multimeter it's as simple as tracing your wires. It would be MUCH easier if you also know how to read a wiring diagram and have access to one. Possibly a defective dimmer switch, you just may not have noticed it with the regular bulbs installed. Good luck!
Theres enuff residule electricity in the wires in the lighting circuit when the ignition is on , even when everything is off , to power led's very dimmly ( 1 volt or less will light up very dim ) . If you intend to stay with LED's , wire in a diode between the + and - wires so theres no backfeeding and that should solve your problem .
) . If you intend to stay with LED's , wire in a diode between the + and - wires so theres no backfeeding and that should solve your problem . I also noticed (and I dont know if this is normal or not but it doesn't seem like it) with the multimeter I checked the voltage going from + to + and - to -. However with the + to + and the - to anything around the dome light just to ground it I was getting a full 12v.
Sometimes it just depends on the brand of LED and/or the color of the LED. LEDs draw so little energy to light up, compared to the stock filament bulbs, that whatever residual power is going through the wiring can be enough to actually light the LED up a tad. A couple of Mom's green LEDs had the same issue. I switched a couple of the LEDs out with another brand, and whallah! Problem gone.
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This I know, I just don't understand why I have power coming through there while the car is completely off.
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Verdad Gallardo Because with the battery connected, ur always gonna have a little power going through your wiring. The stock bulbs need about 1Amp to power up. LEDs need like, only .001 Amps to power up. So, depending on the color/brand/resistor of the LED, some power might make it through to the LED and light it up a bit.
he mentioned having 7 volts though. THAT is definitely not normal. Check for voltage with both doors closed and the car running (you want to be sure you're not checking for voltage when they're SUPPOSED to be on)
Power cycle everything. Open/close the doors, set/unset the alarm, unplug the cabin lighting fuse, start the car and lock the doors, unplug and replug the battery, pretty much anything you can to get the BCM to turn the lights on and off. Another thing you should check is the polarity of the lights and to check if the solder joints on any of the LEDs are touching any of the metal reflectors on the car.
Because with the battery connected, ur always gonna have a little power going through your wiring. The stock bulbs need about 1Amp to power up. LEDs need like, only .001 Amps to power up. So, depending on the color/brand/resistor of the LED, some power might make it through to the LED and light it up a bit.
Power cycle everything. Open/close the doors, set/unset the alarm, unplug the cabin lighting fuse, start the car and lock the doors, unplug and replug the battery, pretty much anything you can to get the BCM to turn the lights on and off. Another thing you should check is the polarity of the lights and to check if the solder joints on any of the LEDs are touching any of the metal reflectors on the car.
I'm still getting the same thing everytime. I have discovered though, with the + on the multimeter to the + for the light and - to - I get the 7 volts unless the lights are on then I get 12. Now with the + to any ground on the car I get a full 12 volts however I didn't check this when the light was on only when it was "off".
Now if I have - to - and + to any ground I get -4 volts which means I have power coming from the - which I'm no electrical engineer but I don't think that is supposed to happen. WTF is going on?
And of course when I removed the fuse and tested I got nothing.
Now if I have - to - and + to any ground I get -4 volts which means I have power coming from the - which I'm no electrical engineer but I don't think that is supposed to happen. WTF is going on?
And of course when I removed the fuse and tested I got nothing.
I had been meaning to ask you because I saw your thread where you replaced the bulbs with LEDs
Just check it in the dome light. That's where I've been checking mine.
Just check it in the dome light. That's where I've been checking mine.
