I diffed your 2005 code to the Default code released by FIRST and, as expected, it is identical.
This makes me believe that your compressor and/or pressure switch is wired incorrectly.
Try making the following modification and see what you see
Code:
relay5_rev = p1_sw_aux2;
relay6_fwd = p3_sw_aux1;
relay6_rev = p3_sw_aux2;
relay7_fwd = p4_sw_aux1;
relay7_rev = p4_sw_aux2;
relay8_fwd = !rc_dig_in18; /* Power pump only if pressure switch is off. */
relay8_rev = 0;
/******************/
/* THIS CODE IS ADDED */
printf("Switch %d Relay %d\r",(int)rc_digin18,(int)relay8_fwd);
/******************/
/*---------- PWM outputs Limited by Limit Switches ------------------------*/
In the case that the switch always shows 0, your compressor is wired incorrectly. If the relay is showing green, doublecheck the compressor's connection to it. If the relay doesn't change color, check the PWM connection between the relay and relay port 8.
If you see that the switch is always reading 1, then your compressor will never turn on. If that is the case, your switch may be wired incorrectly or defective. To verify this, remove the ! from the line that sets relay8_fwd. If the compressor runs and shuts off at 115 psi, then there's some weirdness on why your switch is returning an inverted value. If the compressor never shuts off, doublecheck all connections between the switch and the RC.
Hopefully that helps...