[Al Skierkiewicz]

philso,
The indication is that you might have a loose connection somewhere at the input of the Spike. This could be a bad crimp or a poorly made termination at the PD. You could have a bad breaker in the PD or it could be not fully inserted. Or you may simply have a bad PWM cable such that the return line is shorted to something. When you add the load, the input likely falls to below 5 volts or pulls the control wiring to some "off" state. There is also the possibility that the DSC power has a problem. Always check to see if there are three LEDs brightly lit on the DSC. Then check for correct operation of the LEDs that feed your relay output.