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LED Turn Signal/DRL problem

lextoy

Seasoned Member
Joined
Mar 29, 2014
Messages
402
Location
philadelphia
My XLR/V(s)
2007 Liquid Amethyst
Recently installed all new LEDs in the headlights. With the switchback LED for the turnsignal/drl.
They were working great. white light for DRL, and automatically switched to yellow for turnsignals.
Well yesterday DRL switchbacks stopped activating, started acting weird.
What wires can i check, what fuses? can i reset the ecu by disconnecting the battery, where is the flasher for the turn signals, would this pop up on the tech2 ?
Currently neither drl come on.
Right side: no drl, yellow light comes on constant instead. very weird. that should jut be the turnsignal.
right side turn signal blinks.
Left side: no drl, no yellow light, and no turn signal blinking either.
note both rear turn signals work fine its just the front bulbs not acting correctly.
all other bulbs in headlights working normally.
any ideas. this is going to be pita to figure out.
 
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update
when using the 4way hazard lights (different flasher correct?)
rears flash fine
front right flashes fine
front left still no flash
so i i think this indicates either no power at all going to front left turn signal/drl circuit
or the led switchback bulb circuitry got cooked completely.
the front right has power but only activates the turn signal as the drl, or flashing when called for.
i have the old incandescent bulbs i could swap in.
but thats gonna be a few days before i get a chance. and i'm trying to avoid pulling the headlight assembly until i have a definite solution.
are there light ground points i could clean up? wouldnt they effect the whole assembly, not just the drl? all the other lights are working fine.
here are the grounds...
 

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What are you using for switchback functionality?
No flashers in the system. BCM controls the lights. Common ground for all the lights.
Really sounds like the bulb/circuit you are using for the DRL -switchback is bad.
 
I would disconnect the headlight plugs and make sure they are dry and no corrision. Grounds can be funny. Both of the ones on top of the front frame rails should be cleaned.
 
Yup I will do that tonight after midnight when I get home from work.
Update, i didn't do anything yet... Now both orange blinker LEDs are acting normal. Right one doesn't think it's the DRL anymore. And left one works again. Both blinkers working normal again.
But both DRL don't function. At least now it's acting normal enough I'm not annoyed. The bright white DRL function was really nice though. Have an email in with SuperBrightLEDs to see if they have any experience with this.
another update. cleaned the big ten pin? headlight housing plugs with QD contact cleaner.
went to test, left blinker is dead again. will do grounds and jiggle all the wires while i have the blinker on to see if i can find something loose. i might pull that housing tonight and test with the old bulb.
 
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Ok latest news. Looked at grounds they are very clean. Pulled the headlight housing and ohm tested several bulb bases and grounds have continuity. It's not a ground issue.
I did fix the orange flasher issue on the left side. With some wiggling of the bulb I discovered...Tiny contacts on the base of the bulb are way too recessed. So I pried them out. Also pried out the socket contacts that were much beefier. It wasn't those but that can't hurt. Voila perfect flashing every time. That sucks that it was a poor bulb contact. Took a bit to diagnose. Still no DRL activation. I plugged in my tech 2 and I see that the BCM is registering bulb out for the signal/DRL. I wonder if that has an automated function to disable the DRL then? Unfortunately I didn't save the old bulbs, so I couldn't swap it in. Will go grab a pair at NAPA and test.
 

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DRL turned off ?? i was wondering about that... it was always working normally.
But now it seems like its off? how do i turn it ON
I have the headlight stalk in auto, and have tried many other settings, combos. Is there a setting somewhere?
Today with the new sylvania filament bulbs 3757A ( i only tested in the left housing that was still out of the car) still no DRL.
It flashed at normal speed.
With the switchback LED bulbs, it hyperflashes, but it was working fine for 2 weeks with the LED and hyperflashing.
shouldnt DRL come on automatically when in AUTO, in daylight. but not at night? that why we turn on the headlights to save the lens... it shuts off the drl function.
There is only one blue/white stripe wire that feeds power to the socket, the other two wires are black grounds. i think the voltage is sent right from the BCM, always thru the blue wire?
so when its a blinker it flashes, when its not the blinker it should be continuous voltage. all from the blue wire. so if i have power for the blinker, then the power/grounds are good.
its like its not sending any signal for DRL. i dont think its a bad LED switchback bulb, because the oem bulb didnt work either. at least led and oem bulb both function for turnsignals now.
so i can get it inspected. lol
 
found this. as i suspected. but why did the switchbacks work for 2 weeks and just stop? and why doesnt it illuminate my amber all the time as DRL? and why dont the old bulbs work ?

quoted from an old thread

I think I may have figured out why the 'switch back' LED bulbs do not work with the XLR. I think both the DRL and Turn Signal use the same element of the bulb (the lo element). The control module energizes the element for the DRL function whenever the car is taken out of Park (unless the driver turns the DRL off). Whenever the Turn Signal function is engaged or the hazard flasher is engaged the control module periodically interrupts the DRL circuit and makes the single element flash. If the DRL is off by either driver choice or by having the headlights on, the control module energizes the circuit to make the bulbs flash as needed.

If I understand the 'switch back' bulb it is a standard dual element design (3157) with the lo circuit the 'white' set of LEDs and the hi circuit the 'amber' set of LEDs. The bulb has some form of limiter to turn off the white LEDs whenever the amber circuit is engaged. Since the XLR appears to use only 1/2 of the elements in the 3757 bulb the switch back will never know to activate the amber LEDs since the hi element does not appear to be used by the XLR circuitry. At least that is my theory on the operation.

from here
 

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