Put in heater core now my headlights don't work.
 

I had to drop the steering wheel and take the dash loose, I mainly pulled the passenger side back to access the heater core. I unplugged 4 electrical connections on the passenger side but I didn't take anything loose on the drivers side. Has anyone had this happen and can save me some time looking for what is unplugged?
My parking lights work and all brake/tail lights but no headlights. I looked under the dash on the drivers side and couldn't see anything that looked unplugged.

If you didn't have the battery disconnected during the repair, I'd start checking fuses.

Battery was disconnected, and I checked the headlight fuse under the hood.
BTW this is on a '97 Ram 1500 with the 5.9L

check the switch. i have a 95, i started smelling a sweetish smell, thought it was my heater core til i lost my instrument panel lights and then my tail lights (found that out by getting pulled over by a cop) the parts guy at the local dodge dealer said the switch/pigtail had a tendency to burn/melt and cause problems. pulled it apart, switch was fine but pigtail was a melted/burned mess. 30mins later and a new switch/pigtail everything was fine

I'll check the switch but I'm really thinking something is just unplugged. That would be quite a coincidence for the switch to go out at the same time.
I also replaced my intake gaskets and did the kegger mod as replaced the plentum plate. I don't see how that could cause this, unless there is a plug under the hood somewhere that might be unplugged. It's weird that everything except the headlights work, all parking lights, dash lights brake and tail lights.
I may have to drop the dash again and make sure everything is still plugged in.
Anyone else have an idea?

Check any grounds you messed with

Do either of the headlights work? High or Low beam? Does the little lite in the dash come on when you hit your high beams? If not..... have a look at the multifunction switch. Some wires may have pulled, or, a connector might be loose.

Well it turned out to be nothing I guess. I hit the dimmer switch to see if they worked on high or low and they came on immediately, and work perfectly now. Maybe something to do with dropping the steering wheel put something out of place and it required the lever movement to re-activate it? I have no idea but they're working now. I'm just glad I didn't have to drop that dash again!

At least it works. :D

My father in law drives a 95 Dodge 2500 diesel and some mornings he will turn on his lights and everything will come on except his headlights. After 10-20 minutes they will come on by themselves. It's almost like they are warming up. We can't figure out why this is happening, doesn't bother except when he comes over to pick me up to go deer hunting.