So this has been driving me crazy for a long time now. When driving with the lights on, the lamp out light comes on (along with an annoying beep). The issue is the light flashes on and off and is annoying. It never stays on for more than a few seconds. And sometimes i can drive with the lights on and it doesnt come on at all. The few time i have been able to get out of the truck with the light on, when i check all of the trucks lights they are all working. I am assuming that there must be a short somewhere in the system. is there some way to narrow this down? has anyone else fixed a similar issue that can at least give me a few trouble spots to check?

 

What year truck? Yes, I had the same problem, turned out to be the rear taillight assembly. I took it all apart, (took photos if interested) and did a temp fix on it that lasted maybe 2 months. All the circuitry is basically connected with a common metal bus that was coming loose per their design.

Easier to just go buy a new one, wasn't very expensive.

and, yes, it drove me nuts too until I found it.

 

either a brake light....or the light under the hood

 

could be a ground that has loosened off, i had that and it was the same intermittant ding every time i would hit a bump.

 

Could be 1 bad bulb. I had that for about 6 months until finally a rough gravel road shook the bulb enough to permanently kill it. Was a brake bulb for me... wouldn't happen till I used the brakes. Then sometimes would work again, sometimes for weeks at a time. Of course, it was just that 1 time when I braked and it didn't work that the stupid lamp out lit up and binged. Everytime I tried to see what bulb, it was working as I was stationary.

Some guys have also reported corrosion in the light sockets causing this....

 

+1

we always figure a light is good, 'till it ain't good no more.. you know, you go to turn it on and get that brilliant flash before the bulb goes dark forever.. that's when WE discover it's bad.. but on a circuitry level, the impedance of the bulb starts to fluctuate wildly a good time before the bulb stops working.. These dang trucks rely on impedance to determine when a bulb is about to go- and will forewarn you... but, they won't bother to tell you which bulb it is about to blow.. which is pretty frustrating..

I reckon the engineers were thinking, if they were thinking at all, that in a perfect world (to engineers, the world has little variance) all the bulbs should be replaced at about the same time, and therefor when you get that floggin' ridiculous DING and divert your attention to the cluster to briefly catch the 'lamp out' light just before it dims (which happens likely less than 3% of the time) you should drive right dang NOW to the parts store (if you don't you will suffer torture of the DING variety) and buy a complete new set of bulbs for your truck.. Yes, that was a run on sentence, but that is the purpose of the DING and fleeting light, to make you crazy and use run on sentences..

the weakest bulbs in the circuit are the brake lights in the tail lights. Those are the ones under the most stress because they are being used dual circuit (when your running lights are on AND when you mash the fat pedal), so- start there.

 

Yes.
My dad's truck had this exact problem too, turned out the left blinker bulb in the tail light was trying to go. Finally went when he hit a speed bump fast.