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All exterior lights flashing with turn signal.

08-20-2016, 08:32 PM
I just replaced all my exterior lights, but now during the daytime, when the headlight are not on, and I use my turn signal (regardless of direction), all the exterior lights flash (excluding the headlights, the back-up lights, and the high mounted brake light). But when the headlights are on, the lights flash as they should (left and right indicators). Any ideas as to what is causing this.

Blue Bowtie
08-21-2016, 12:41 PM
What model year?

08-21-2016, 01:09 PM
2002 Buick Lesabre Custom

Blue Bowtie
08-21-2016, 02:07 PM
Do the signal lamps operate normally if the four-way hazard flasher is used? It may be useful to exercise the four-way switch a few cycles just to be sure the contacts are clean and completing the circuits.

The second most suspect item is a malfunctioning turn signal (multifunction) switch. Of course, all lamps must be intact and properly grounded for the system to function normally.


08-21-2016, 02:14 PM
The hazards flash the same as the turn signals do, the wierd thing is that when the headlights are on, the turn signals and the hazards flash as they should.

Blue Bowtie
08-21-2016, 02:29 PM
I would be suspicious of grounding in at least one lamp circuit. If one of the front turn or side marker lamps is not properly grounded the power may be feeding back through the headlight filament to the rest of the running/marker lamps.

It might be easiest to remove one lamp at a time, starting at the front, and see if the phenomenon continues.

08-21-2016, 05:36 PM
Alright, I'll try that on my next day off, thank you for all your help so far.

Tech II
08-22-2016, 10:01 PM
I agree with Blue, especially if it wasn't doing this before you replaced all the bulbs.....

Could have a bad bulb, or a bad socket, as Blue stated.....going one bulb at a time, should pinpoint the problem....

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