The model is a ford 350 and year 2000. I like mister_e's idea. I also need to know whether or not the horn wire is positive. I also need help in the code you sent me.

AmountOfPulses = GPIO & $0F ' Get only value of GP<3:0>

I assume that it reads those pins and stores the value in the variable. I need to know how it does that and how does it adjust from 0 to 16 pulses with only three switches. I can access the wire from under the dash.

P.S. My Name is Albert