I have a 2000 F150. I've never had an electrical problem with it ever - until I did the following below. Now when I turn my headlights on, they stay on - even when I turn the switch off. And the illumination lights don't come on at all either. I have to pull the fuse to get the headlights to go off.
Here's the background: I got an old horse trailer with the wiring harness ripped out, I had to figure out which wires went to where. I did that, configuring the wires to a 6 plug. The trailer has electric brakes and so forth, so I went to the trailer store and they sold me an under dash electric brake controller. My newer Ford Truck had directions & a harness for hooking up such controllers - it was really quite simple.
At first everything worked great -all the trailer lights worked (running lights, brake & turn lights) and all the truck lights worked, and the electric brake unit worked - on my first try. Then I went to pull the trailer out of the garage and I started the truck up, and I noticed the running lights were not comming on the trailer. As they are controlled by the light switch in the truck cab, I went to switch it on and off - and I found the lights would not switch off. So began my trouble, and so it remains: I can turn the lights on, but once on they will not turn off (unless I pop the hood and pull the fuse). And the dash illumination lights will not come on in any circumstance at all now. All this even when the trailer is NOT hooked up, and all this happens even when I disconnect the new Electric Brake Harness & put everything back like it was before I started fiddling with it.
Again, mine is a newer Ford truck, I've never had an electrical problem one until now. I'm worried that I fried something?
Any ideas on troubleshooting this. I've pulled all the fuses, none are burnt. I don't know where else to look!
I would greatly appreciate any advice on this!