Rectify the coil output and then read it with an ADC pin on the PIC.
With a little experimentation, you will not only be able to see if the load is on or off, you will also be able to tell what the load is.

Say the max amps in the load circuit is 20 and the ADC is 8 bit. Set the VREF so that 20 amps reads 255 at the ADC. Then 127 at the ADC would indicate 10 amps on the load circuit. Or there abouts.