I think it might be that the connector to the horn has come off (this is not that unusual). If the interior lights are connected in series with the horn, they would go as well. The horn connector is found sometimes in the horn pad, or in the dash just under the instruments, or within the steering column cover.

The internal light and the electric window regulator may be two separate problems, but could be related. Don't be surprised if these are not related. The simplifed checkout procedures found in repair manuals may indicate a bad switch assembly - but don't believe that right-away without further checks. Sometimes, the problem is broken wires in a boot going from the door to the body. This bundle flexes each time the door is opened and wires have been know to part inside their insulation without breaking the extruded insulation. Such breaks usually happen with the driver's door, although the other doors are not totally immune. The driver's door has the big bundle. Remove the switch assembly and check it for continuity in all switch positions before replacing. Hopefully, John_G will chime in and tell us more. He knows about the various methods that Ford uses for controllng the interior lamps

This time last year this happenend to me, wd-40 did not work! After $300 and a lot of time on-line, I got a refund check for $215 from Ford. This is a common problem! A couple of other things to watch for is the rear wheel bearings it is also common for them to wear out, The wheel bearing are covered under 100,000 mile warranty, however, according to Ford the wheel bearing cannot be purchased alone, it comes in a hub assembly which is not covered! Tricky! They ended replacing both rear wheel bearings for the deductible of my warranty $100 vs $250 each! The other is the head. Took the car in for scheduled oil change and found the head was warped. They fixed it, the next week after finding oil under the car, they replace our engine. Good Luck!

Quirky said "Get used to that check engine light. It's a ford, it put in it's 3 years and now if you still want to use it, you're gonna have to pay. You may as well toss it now, take it to a dealership and trade it in as your down payment." The advice of trade it in as a down payment, is only good for the people that make their living selling new cars. Similarly, the people who learn to fix cars, "CORRECTLY" I might add, totally disagree with that logic for very sound reasons, not just the fact that this is how we make our living. Being a Ford does not make it any more, or less prone to requiring service, and check engine lights are simply just an extension of what a service tech has to deal with. Now from the facts that there are roughly 2000 possible faults that can trigger a check engine light on that Explorer, there could easily be more than one thing that needs addressed over the next few months, and especially the next few years. Most of the time the only thing consistent will be the lamp coming on because of the sophistication built into the system that allows it to compensate for identified problems. The long and short of the trade it in instead of keep it and service it mentality is "TENS OF THOUSANDS" dollars more spent always driving something new VS the actual cost of keeping them fifteen to twenty years, and two to three hundred thousand miles. There is money to be made by the average consumer by spending some on long term service. All you have to do is look at the first person trading in and being upside down on the equity, and then just look at how much could have been repaired for that same amount of money, IF, and I repeat IF, the car actually needed repairs! Yea Bob, reading it again, I see what you are saying. She could have been blaming the year of the car, an 02, instead of talking about an O2 sensor. But scrolling back, on my computer it does look like she hit the letter O, not 0 a number. So right away my thoughts would go to the oxygen sensor. Oh well it's hard to say sometimes, that's why when I am writing things anymore I put a / through my zero's otherwise I might not remember what I wrote :)...