Pulled up to the gym this weekend and saw my truck's reflection in the glass. I had not realized that one of the running lights (nomenclature??) was out on my '15 Silverado.

The truck has 2 lights vertically oriented on each side, and the top light on the right side was out. I dutifully stopped in at Autoclone and picked up the proper bulb, then went thru the hassle of removing the air filter and housing, reaching around through the side panel and replacing the bulb. Got it all back in, and when I cranked it up, it wasn't working. Disassembled everything, repeated the process, and clicked the remote button, and was rewarded with a blink like the other lights. Mission accomplished.

Today I pulled up at the same spot, and again note the light isn't on. After some investigation, here is what I find:

1) when your lights are on (daytime running mode), the light isn't lit like all the rest

2) If you turn on your turn signal to the right side, it will blink

3) if you click unlock or lock on the truck, it comes on for a brief time like the others do

4) looking at fuses, nothing appears to be blown.

If someone can talk me through this, I would appreciate it. Back in the day it was a simple thing to find gremlins, but nowadays they seem to come with computers and PhD's in frustration.

Is there a plug from the whole light assembly to the wiring harness? Not the sockets for individual bulbs, but the plug for all of them. I'd check that for corrosion. We did have some road salt / spray this year in the mid south.

I would probably try switching bulbs with the other side at this point.

Good question. Problem is, you can't see squat down in there, because these side lights are literally accessible only via a cutout in the body panel.

Would look something like this.

I'm obligated, by the Terms and Conditions of the Forum to suggest you park where you can't see the reflection of your truck, thereby solving this problem.

Can't find any wiring disconnected. Thoughts? Any fuses that would do this?

It's part of the GM plan.

That is a mystery. The truck is not that old. Any chance it started when you changed out a headlamp?

The H11 low beam behind my air box on a '13 has awfully short wiring.

Sounds like a double element bulb. If it is, try and get a look at the contacts in the socket, one of them may be corroded and preventing contact for the running light element.

Sounds like you need a circuit diagram. You have three inputs and all but one doesn't work. Maybe they have a processor or diode network that switches on the three conditions.

 
The "one running light is out" phenomenon has been an issue for years in all GMC light truck lines (Sierra, Silverado, Yukon, Suburban). It is almost their trademark.
 

it's probably nothing that can't be remedied by a series of increasingly expensive and difficult parts replacements, culminating with the computer.

I broke down last night and disassembled most of the upper front end to take out the right headlight assembly. Took out that dust cover thing over the radiator and front cap, then the grill, then the lower valance, then the headlight. Joy. Nothing was out of place that I could see, though I did undo and re-snap all of the connectors.

Once it was out so I could manipulate it, I plugged it back in and started testing bulbs. I still had all of the bulbs that were removed or swapped, so I went through each one individually, flipped them 180 degrees if they didn't work one way, etc. Strangely, none of the 7443 Sylvania replacement bulbs would stay on when they were supposed to, yet the OEM one did. Removed it and put in the replacements, nope. Put original bulb back, yep, works perfect.

So, reassembled everything and it works great now. Can't be a short, since the issue was repeatable with the replacement bulbs, but had to be something going on since the original bulb was initially doing it as well.

I chalked it up to Gremlins, and will keep an eye on it. If it continues, I'll wait for Harbor Freight to have a special on the flamethrowers and then burn it with fire....

quote:

Originally posted by slabsides45:

I chalked it up to Gremlins, and will keep an eye on it.

I refuse to believe the under perfect conditions of bumps and temperature, my CD/MP3 will advance one chapter when the wheel is turned to a hard left ... Clearly, it is the Gremlins at work.

I'm halfway through a 5,000 road trip. One of the first things packed is a box with OEM bulbs, H11 thru license plate bulbs. gmpartsdirect has decent prices.

I would check the resistance of the two different types of bulbs. It is probably controlled with a processor and the different bulbs have a different resistance.

Were the replacement LED or standard bulbs?

The standard bulb shows 25/5.9 watts while the LED is 1.7/.7 watts.

quote:

Originally posted by 41:
I would check the resistance of the two different types of bulbs. It is probably controlled with a processor and the different bulbs have a different resistance.

Were the replacement LED or standard bulbs?

The standard bulb shows 25/5.9 watts while the LED is 1.7/.7 watts.

They were just standard bulbs. Sylvania LongLife 7443, I believe.

I have a 2000 Silverado and fought this same issue for years. I replaced bulbs singularly, then in pairs, different model numbers, flipped, etc... The bulb sockets notoriously burn out. I've bought & soldered in new sockets. Used dielectric grease, tried dry....

The solution was changing both DRL bulbs with LEDs. I guess they draw less power and wont burn out the socket. I used amber LEDs and think they look better & brigher. (All other bulbs are traditional) Its been months and still working great.

Like mentioned earlier, its a common issue on all Silverados, Tahoes, Suburbans, etc. Start looking at any when your driving & will be surprised how many are winking at you.

Sounds like the socket must be plastic and the heat causes the contacts to embed in the socket.

The LEDs would be a good replacement since they draw only 1.7/.7 watts versus the 25/5.9 watts of the standard bulb.