Horn blows when I turn on headlights
 

Went to leave for work this morning and when I turned on my headlights my horn started blowing and windshield wiper fluid started spraying. I unplugged my horn and the wiper fluid stopped after about 10 seconds. The pump stopped running, I didn't run out of fluid. I shut lights off and turned them back on same thing, fluid for 10 seconds and then it stopped. When I got to work, for the heck of it I pressed my horn after I shut off my lights and my running lights came on, headlights didn't come on. Anyone have any idea of what the heck is going on? Thanks

Sure ! The horn relay gets activated when you depress the horn button/pad.It seems you lost the ground for the steering column so the horn relay is using your wiper washer and lighting circuit for it's ground, AND when you turn the tail lights on they are using your horn relay circuit for it's ground. I would suggest that you start at the battery negative cable and check every ground connection you can find/see and you should find one of them either broken or corroded to the point it will not complete the ground circuit . Be patient, you will eventually find it . Don't overlook the grounds for all the sheet metal.
Is your light switch located on the steering column by any chance?

Thanks for the info. No, the headlight switch is on the dash. Since my original post, after the washer fluid is done spraying the wipers stay on and run at full speed and do not stop! I googled my problem and some posts I have read on other sites make reference to a multi-switch. It sounds like this module is about $200 and has several circuits running through it. This is the 3rd Ranger I've owned and have never had anything close to this happen. I will certainly start with checking for a bad ground.

OK... Now the plot thickens. I pulled my truck into my shop and the wiper fluid pump came on. I noticed that it "skipped" so when I got it in the shop I pressed the horn and the running lights did not come on. I plugged my horn and my windshield wipers back in and everything is normal except for the fact that when I turn on my park lights my fluid pump still comes on! I found several grounds, I plan on going through and cleaning them to see what happens.

Sounds like a wire is corroded or loose and just contacting the circuit intermittently. The skipping is just the wire making very poor connection with whatever it is using for power or ground. :(