Chevrolet equipped the 2004 Avalanche 1500 with a 5.3-liter V-8 engine and four-speed automatic transmission. The Avalanche 2500 came with an 8.1-liter V-8, also with a four-speed automatic transmission. Both trucks came standard with a fully automatic headlight system that included daytime running lights.
Your Avalanche has three fuse panels. Two are located in the passenger compartment, which is where you might expect to find fuses for the lighting systems. The fuse and relay for the daytime running lights, however, are on the fuse block in the engine compartment. The underhood fuse block is on the driver side of the engine compartment on the wheel well and behind the battery. Lift the cover to access the fuses and relays. There is a relay and a fuse, both labeled DRL.
The DRL system operates when the ignition switch is on, the truck is not in "Park," the exterior light switch is in "Auto," and the daylight sensor detects light. If your daytime running lights aren't coming on, make sure there's nothing thrown up onto the dashboard blocking the light sensor, and make sure the exterior light switch is in "Auto." The exterior light switch is located on the far left side of the dashboard below the left air vent.
