I had a similar issue when I wired a SPDT switch on my 1st Sling to turn the headlights on when up and the demon eyes when down. I ended up using a diode to separate the 2 circuits. A diode will allow electricity to flow one way but not the other. It was a while ago and I'm a little confused by the reverse wiring but I believe you would install it on the demon positive so that it can flow to the switch. Then the hazard positive can't flow to the demon ground. This is just a guess aznative75 but diodes are cheap and this would be relatively easy to try.