2007.5-2010 GMC Duramax LMM Fog Lights

Which Sierras came with fog lamps

GMC sold the heavy-duty Sierra in three directions and fog lighting followed the trim. On SLT the halogen front fog lamps were standard. On SLE they were available, which means some have them and some never did. On a Work Truck they arrived only through the SL and Work Truck Preferred package. Two 2009 Sierra 2500HDs parked side by side, same color, same box, can differ at the lower corners of the bumper for that reason alone. Before you shop for anything fog-lamp related, find out which of those three trucks you own.

Reading the truck first

Start at the bumper. If there are lamp openings with lamps in them, you have factory fog lighting and you are dealing with a lamp, a bulb or a circuit. Blank openings mean GMC never installed the hardware, so the lamps and the harness behind them are both missing. A Sierra ordered with Snow Plow Prep is a slightly different case: that option ran forward lamp wiring and roof lamp provisions, so there is more in the front of the truck to work with, though it is not the same thing as having been built with fog lamps. The window sticker or the VIN settles all of it.

Fixing a lamp vs. changing how lamps behave

Those are two different jobs. A broken lens or a dark halogen lamp in a bumper that already has the hardware is a straight part swap, and nothing about the truck's wiring changes. The second job is not about the lamp at all but about what commands it, and that control side is what the part listed here deals with. Nothing in our research points to a factory fog lamp failure pattern on these trucks, so we will not hand you a mileage number. A lamp comes out when the lens is cracked, when water is sitting in the housing, or when it simply stops lighting.

What we carry

The one part listed here is the All Lights On module from Fleece Performance Engineering. Fleece catalogues it against the 6.6L Duramax engine family, 2007.5 through 2025, which is why a Sierra's trim and box never enter into it, and its product page is the place to read what it switches and where it ties in. A replacement halogen fog lamp or bulb for a GMT900 Sierra HD is not listed on this page, so phone the shop with the VIN and we will chase down the right part number for your build.

Fitment notes

Sort the body out before anything else. GMC kept selling the GMT800 Sierra HD into 2007 as the Classic, and it wears GMT800 lamps, so a 2007 Sierra only lines up with 2008-2010 if it is the new body. Within the 2007.5-2010 run itself we found no lamp interchange we are willing to stand behind, so treat every listing as verify-by-year-and-body-style and let the part number and the fitment checker on the product page settle it. What the order sheet did matters more here than how the truck was configured, since trim and packages are what decided the bumper hardware. And do not read anything across into 2011, which is a heavily revised heavy-duty truck running the LML in place of the LMM.

Frequently asked questions

Is the All Lights On module a fog lamp?

No. It is a lighting electronics part rather than a bumper lamp, and it is on this page because it belongs to the fog lighting side of the truck. Its product page spells out what it controls and how it connects. If you are shopping for the lamp itself, call us instead and we will sort out what your Sierra was built with.

One of my fog lamps is out. Is that a known problem on these trucks?

Not one we can point to. The research we trust does not document a factory fog lamp failure pattern on the 2007.5-2010 heavy-duty trucks, so we are not going to invent one for you. Treat it like any other lamp: check the lamp and the bulb, then the circuit behind it. We can test it in the shop if the answer is not obvious in the driveway.

Can you tell from the VIN what fog lighting my Sierra has?

Yes, and it is the quickest route. The build tells us whether the truck left with SLT-standard fog lamps, the optional SLE lamps, or the Work Truck package, and therefore what is sitting in the bumper and the harness. Call the shop with the VIN before you order a part. It takes a minute and it saves a return.

If I change my headlights, do the fog lamps change too?

No. On these trucks the fog lamps are separate halogen units low in the front bumper, independent of the headlight housing, so a headlight swap leaves them exactly as they were. If you want the whole front end sorted at once, work through the headlights page for this truck alongside this one.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.