Headlights not working - 2004 Jeep Wrangler

[MackinVA]

I have a 2004 Jeep Wrangler X, original owner with 130k miles. My passenger side headlight went out and I replaced it and everything worked fine. A week later both headlights quit working. Running/fog lights & tail lights work fine. I replaced the headlamp fuse but no luck. What should I check/replace next that could be the problem? Thanks