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'95 LS ... Dome & Map LED's Killed themselves and my vanity lights
Well, I went and installed LED's in my dome and map lights ... Something I've done in many cars before without a problem.
They've been in there for months.
Noticed them flickering here and there (more so lately) - just figured they were dying from terminal cheapness.
Low and behold, All three are now dead, along with my visor vanity lights ... and it's not the bulbs (clearly if they all went out at the same time) or a fuse.
I am seeing posts about led dome lights taking out the door computer. Is this a thing?
Mine already has it's issues (intermittent control of the windows from the master switch) but this is new. And i hate it
Can anyone confirm this happening to them and how they solved it?
I have seen many Celsior owners have experienced the same problem with you trying to use LEDs instead of incandescent bulbs . You probably need to replace the body computer or ask someone who is capable to repair it. The current controlling circuit in the body computer is often damaged due to the excess current.
Thanks for getting back to me. It's always something.
I was always under the impression that LED's drew less of everything (wattage / current).
So I guess that is not the case?
The lights in the foot well and doors seem 100% fine, are those running on a different circuit?
Yes, it draws far less current but there happen failures of the body computer time to time around me. The current flow of an LED chip is mono directional and the current flow should be from the anode to the cathode. When reversed, there should be no current nor no light emission but a well made LED module/unit has a surge protection diode in parallel with the LED array with the reversed polarity aiming to pass through the reverse surge current which is harmful to LED chips. The protection diode passes through a big current when the LED module/unit is reverse installed. In that case, there is no light but the current is too much. When the owner noticed that the direction was not correct and there was no light emission, it's already too late because the drive circuit is already damaged due to the too much current. When you install an LED module/unit with a protection diode, you have to be very careful for the polarity.
Other than the protection diode issue, there are some low quality LED modules/units on the market that kill the driver circuit, I need to add.
sorry to hear about this. never heard of cheap LEDs blowing the body computer, but Yamae is our resident electronics expert so believe him!
i ran LEDs on my vehicle but recall them needing to be clocked a certain way or they won't light up at all. perhaps cheaper LED bulbs lack this diode Yamae mentioned. bummer!
sorry to hear about this. never heard of cheap LEDs blowing the body computer, but Yamae is our resident electronics expert so believe him!
I sure do. He's got a big footprint here on the forums and a wealth of knowledge. This particular unit was going to be changed soon enough anyway, it has been giving me grief elsewhere. Window controls mostly (not the switch, i tested it). Really sucks opening your car door at night and ... nothing
Originally Posted by timmy0tool
i ran LEDs on my vehicle but recall them needing to be clocked a certain way or they won't light up at all. perhaps cheaper LED bulbs lack this diode Yamae mentioned. bummer!
Yep. The LED's have a polarity. I really don't feel like pulling a door panel off but ya gotta do what ya gotta do.
This circuit diagram is one of drawings of the page and as you see, the diode TVS draws the big current when the voltage supply is reversed. The Resettable fuse is not used in the body computer and the big current damages the drive circuit.
This is interesting to learn. When the voltage supply to the LED circuit is reversed, does it act like a short, or does it supply additional current somehow? I would think a short should be harmless since it's as if the LED didn't exist at all. But if it supplied its own transient current, then it makes sense that could damage other components.
I found an article explaining that diodes can store some charge and cause trouble. Is that what's happening here?
Mostly beyond my level of comprehension unfortunately.
The foot-well lamps and door courtesy lamps (also LED) are functioning without incident. Are those on a different circuit than the dome and vanity lights?
Mostly beyond my level of comprehension unfortunately.
The foot-well lamps and door courtesy lamps (also LED) are functioning without incident. Are those on a different circuit than the dome and vanity lights?
The photo below is for a 98-00 Celsior and is a bit different from yours but it contains driver circuits for various bulbs and loads. Each bulb has it's own drive transistor and bubs are getting power from each transistor. So there are different circuits each. Those transistors are driven by a processor which controls variety of loads using variety of output ports. It is seldom to fail the processor. Some loads are driven by relays but as long as I know, bulbs are driven by transistors. A person who is good at dealing with transistors may fix the problem. Compared with a model 94-97, a 98-00 is a bit more complicated due to the additional bus control system BEAN but a 94-97 uses simpler circuit.
I think you are right. Wishful thinking on my part. Pretty sure this ^^^ is the one YAMAE was referring to ... not the door computer.
Have you ever pulled one of these out? Does not look fun. Up behind the fuse-box near the steering column or something like that?
I needed a new driver door MPX anyway to fix some power-window problems (which it has from what I can see).
So that's something.
Have not pulled on on your particular car no could be a challenge to get to, yes somewhere near the steering column.
BTW I've blown up a relay integration unit (primitive version of the above) by shorting the dome light. Also LEDs commonly fail and short out, usually not the LEDs themselves but the driver/voltage regulator circuit. This happens in automotive and home LEDs.
10-26-22, 05:08 PM
'95 LS ... Dome & Map LED's Killed themselves and my vanity lights
