Current Symptom: brake lights don't work
What started it: Horn was weak and barely audible since I bought the truck. (sounded like a sick duckling)
Steps I took to get from horn not working to brake lights not working:
- I had coffee and stared at the wiring diagram and came up with a plan
- Once outside, I disconnected wire at the horn and used a length of wire to stretch directly from the positive battery terminal to the connector on the horn.
- It sounded great. (Problem must be up-stream)
- Reconnected wire to horn.
- Removed horn relay from other side of the engine bay.
- Cleaned contacts with vinegar and wire brush and reinstalled and tested.
- Still barely audible. (Could be horn relay or up-stream problem)
- Drove to autoparts store to get a new connectors for the fuel sending unit. Everything working fine except horn.
- Once home, I removed horn button from steering column and removed the little spring-loaded brass contact.
- Cleaned with vinegar and wire brush and reinstalled and tested.
- Still barely audible. (Could be horn relay or bad ground somewhere)
- Got a length of wire and stuck it down in the hole to make contact with the bottom of the cavity where the spring loaded brass contact lives.
- Touched the other end of the wire to the center nut of the steering column that holds the wheel on.
- Still barely audible. (At this point I'm strongly suspecting horn relay is bad since it's very clacky)
- I resolve to buy a horn relay.
- Next morning I start driving to work (in the rain) and find that turn signals and brake lights don't work. Everything else works fine.
- Oddly enough I tried out the horn and it sounds strong and great this morning.
- I check the fuse panel when I got home and the turn signal/stop light (14A) fuse was blown (splattered is a more appropriate description).
- I replaced it with a new one.
- Turn signals and everything else now worked fine.
- Brake lights still did not work.
- I removed the drivers side tail light cover (in the rain) and inspected the bulb. Looks fine. Reinstalled bulb.
- Brake lights still did not work and now the front-passenger side turn signal and drivers side tail light does not work (I suspect water got in the socket when I removed it).
Any ideas on where to troubleshoot next?