Do these fog lights connect to the factory harness, or do I need to run new wiring?

They connect directly to the factory fog light harness if your truck came equipped with that option. If your truck didn't have fogs from the factory, wiring routing will depend on your specific setup — test-fit the connectors before committing to any permanent modifications.

Can I install the switch myself, or do I need to remove the dash?

Switch mounting depends on where you want it located. Most drivers mount them low on the dash or in the overhead console area — no dash removal required for those spots. Check clearance before drilling or adhering.

What's the return window if these don't fit or work with my truck?

Confirm fitment before powering anything up. Once tested, you're responsible for the condition of the components. Contact ModSupply directly with photos and details if there's a real mismatch — they handle case-by-case situations from there.