2001 Ram 1500 Quad Cab 5.9L
I bought new headlight assemblies, and when I went to take the old ones out, there were no bolts holding them in. I've tried 1/4 x 20, 1/4 x 24, M6 x 1.0. The M6 seems to be the best size fit, but it start into the hole but jams, so I am assuming a different pitch maybe. Local hardware doesn't have any other pitches in M6.

So what the heck size are they?

 

On my '96 Ram, they appear to be a self-tapping type of screw. It calls for Dodge part #6034708 (I found this part in the electrical section of the Dodge Ram parts manual for my year truck - you can download the parts manual for your year truck here - https://dodgeforum.com/forum/2nd-gen...s-manuals.html). There are 3 screws per headlights needed to properly secure the headlight to the truck. If you have a pick & pay yard near you, this would be a great place to find them.. I had the same issue a while ago and I found a few at a pick & pay yard..