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My old car, or should I say, my very old car, recently broke down. If it weren't for the fact that I don't have much money, I would have rejoiced in the car's demise. Really, I would have. You have no idea how much pain my old car caused me.
Since I commute to school I had to quickly buy a new car. Of course, when I say new I really mean different, as I'm your stereotype broke college student. I had to settle for an older car with a few problems, with one of those problems being that the horn didn't work right. Oh, it would make noise all right -- no problem there. But instead of pressing the steering wheel to honk I had to press this stupid little button:
According to the previous owner, their mechanic was unable to get the horn working correctly and so installed the button-horn. This reminds me of my previous car, where instead of installing a hood latch, which cost me $10 on ebay, the previous owner or their mechanic cut two holes in the hood, mounted two post thingies in the engine block (which would have actually taken a lot of work) and used two idiotic looking pins to hold the hood down. Anyway, back to the story. After almost getting hit the other day while driving (guess the gender of the other driver?) and not being able to honk my horn easily, I decided to take a go at fixing the horn and getting rid of the dumb button. I removed four Phillips screws on the back of the steering wheel, popped out the middle piece, disconnected two wires and took it to my bedroom which doubles as my workshop. Connecting my multimeter to the two terminals on the back of the horn module showed this:
Using my substantial mental faculties, I theorized that the circuit should be open unless pressed, indicating a short circuit inside the unit. Getting the rubber/rubber-like covering off the module turned out to be a bit of a challenge, as some idiot had glued it onto the plastic. But with determination and my hobby knife, I was finally able to remove it. This is what awaited me:
The top plate of the "membrane" sensor can be seen in the above photo. There are two plates that are supposed to be separated by a compressible insulator which had apparently worn down enough that the plates were always touching. The obvious solution was to simply put something between the two plates to act as an insulator. I took some foam from a box some ICs were shipped in and, after slicing it in half to make it thinner, used super glue to attach it to the bottom plate. I noticed the contacts on both plates seemed oxidized and verified this with my multimeter, so I cleaned all of the contacts by lightly sanding them with 600 grit sandpaper (the same stuff I use when making PCBs) and wiping them off with alcohol. Here's the final product:
After testing it a little and putting the rubber covering back on, the meter showed an open circuit! Great!
Finally, after a moment of apprehension, I tried pressing the horn:
Success! Now all that was left to do was rip the button out of the car, which was a real pleasure to do, and put the horn module back in. The result:
Since I commute to school I had to quickly buy a new car. Of course, when I say new I really mean different, as I'm your stereotype broke college student. I had to settle for an older car with a few problems, with one of those problems being that the horn didn't work right. Oh, it would make noise all right -- no problem there. But instead of pressing the steering wheel to honk I had to press this stupid little button:
See the stupid button??
According to the previous owner, their mechanic was unable to get the horn working correctly and so installed the button-horn. This reminds me of my previous car, where instead of installing a hood latch, which cost me $10 on ebay, the previous owner or their mechanic cut two holes in the hood, mounted two post thingies in the engine block (which would have actually taken a lot of work) and used two idiotic looking pins to hold the hood down. Anyway, back to the story. After almost getting hit the other day while driving (guess the gender of the other driver?) and not being able to honk my horn easily, I decided to take a go at fixing the horn and getting rid of the dumb button. I removed four Phillips screws on the back of the steering wheel, popped out the middle piece, disconnected two wires and took it to my bedroom which doubles as my workshop. Connecting my multimeter to the two terminals on the back of the horn module showed this:
The horn membrane is a closed circuit when it's supposed to be open.
Using my substantial mental faculties, I theorized that the circuit should be open unless pressed, indicating a short circuit inside the unit. Getting the rubber/rubber-like covering off the module turned out to be a bit of a challenge, as some idiot had glued it onto the plastic. But with determination and my hobby knife, I was finally able to remove it. This is what awaited me:
What the horn module looked like after removing the rubber cover.
The top plate of the "membrane" sensor can be seen in the above photo. There are two plates that are supposed to be separated by a compressible insulator which had apparently worn down enough that the plates were always touching. The obvious solution was to simply put something between the two plates to act as an insulator. I took some foam from a box some ICs were shipped in and, after slicing it in half to make it thinner, used super glue to attach it to the bottom plate. I noticed the contacts on both plates seemed oxidized and verified this with my multimeter, so I cleaned all of the contacts by lightly sanding them with 600 grit sandpaper (the same stuff I use when making PCBs) and wiping them off with alcohol. Here's the final product:
I added foam padding (the stuff used as IC packaging) to separate the two metal plates.
After testing it a little and putting the rubber covering back on, the meter showed an open circuit! Great!
Not pressing the horn produced an open circuit.
Finally, after a moment of apprehension, I tried pressing the horn:
pressing the horn resulted in a closed circuit.
Success! Now all that was left to do was rip the button out of the car, which was a real pleasure to do, and put the horn module back in. The result:
The stupid button has been removed.
So now all I have left to do is:- Fix the right turn signal light, which is intermittent.
- Stop the turn signal lever from snapping back three times during every turn.
- Fix the interior light (it's not the bulb
). - Get the right speaker working.
- Replace the radio antenna.
- Fix the gas gauge, which doesn't work.
- Figure out why the washer fluid isn't coming out (the pump runs, but nothing comes out..).
- Stop the passenger door lock from getting jammed all the time.
