Wait.. your side lights are working, right? Why did you replace them in the first place? Pls explain why you chose to replace the sidelights. They don't turn on? You did not mention it, but just in case, a test would be to put the car in PARK by rotating the key the other way - see if the side lights turn on.
The light warning may be the side lights or plate lights (and other lights for various models)
I'm sorry I'm not good help.. not familiar with your car. If all lights work and are the proper resistance, then it could be corrosion or unlikely connection problem between stalk unit and rev counter module.
Since the horns have stopped working:
1) Check horn operation;
2) Check horn fuse
3) check horn relay
4) check steering column spring horn thingie (danger: airbag)
Last edited by Loknar; 06-04-12 at 05:30.