[68c10airstream]

Well my truck to look at for your steering wheel question was being used by a friend and I wasn't able to look till today and I was wrong! The plastic you removed should be there. I would use the bottom of a plastic disposable container and cut a washer from the bottom and install it. To recap it's function is the metal saucer makes contact with the spring loaded plunger all the time so it's 12+ needing to go to ground to make the horn blow.

The saucer piece is loaded with the center dished up at you as you look at it.

The cup that the horn button gets pushed into simply takes the force from being pushed on (to make the horn blow) and makes the saucer piece turn inside out, forcing the back side of the saucer piece touch the bare metal steering wheel center.

Look at it this way, if they could make the cup that holds the horn button sturdy enough out of plastic it would make no difference, the horn would still blow.

The reason for the pink plastic insulator is needed is because the cup is metal and without it the horn would blow all the time.

So the horn button, the metal cup, and the pink insulators job it to turn the saucer's dished surface inside out (more or less) and not ground out the signal in the process.

Remember the electrical circuit is going from the plunger to the saucer piece all the time, and when pushed the backside of the saucer piece touches the center hub area of the steering wheel as it's turned inside out and is then grounded at that moment. So the only thing that has to be good and shiny is the backside of the saucer and where it touches the center hub. Sometimes an eraser works very well for this.