Hey there!
Im in electronic voodoo here with my 02 3.3 Grand Caravan. The horn was not working, knowing there were fuse box issues (from this forum Thanks guys!) I had my Master Mechanic in the family help verify... well to keep a long story short, the horn works! but the car wont run! My buddies on the road...I think he left a power probe and test light with the car, can someone chrip in! help point me in the right direction?

 

Welcome to DF
How was the van running before the horn repair?

 

Last fall it was hard to start. changed the plugs and it ran fine, made it from NY-Fla and back in April no problem

 

Does the engine crank over and won't start or does not crank over. If it does crank over, did you check for fuel and spark?