So on my 2004 silverado when i turn the truck on, in the auto position for the headlights they blink on and off without stopping. When i put the high beams on only one bulb turns on in each headlight. If i put the low beams on to the manual position on the switch the headlights shut off completely but the yellow running lights are still on the whole time. Sometimes the light cuts out and only comes back if i smack the dashboard on top. The cluster lights cut out as well and only come on when i hit the dashboard as well. When i turn the truck off, all 4 turn signals blink for at-least 2 minutes before stopping. Im not sure what the issue could be but any help is appreciated!

 

Sounds like the wiring harness or the term block in the steering column are the culprit. I have a similar problem with my 01 where the low beams will cut out but signals hi beams wipers ect work fine, I've tracked it down to a wire on the harness that connects to the block has come loose. (Just havent gotten around to fixing it yet)

If you take the top portion of the steering column off you'll see where the wiring harness comes up from under the dash to quick connect to a big silver block. Theres about 10 or so wires all clustered together. (Itll be on the leftish side)

Since you're getting multiple things happening I'd guess it's the block itself rather than the harness, especially if a smack gets it to behave.