I had plans to kill the wigwags and revert the lightbar to mode 1 when the car was in park. I set up two relays on the car, one being for mode 3/wigwags and the other being mode 2. I wired the hot side of the relay to mode 1, and the ground side of the relay from fuse 1 on the Crown Vic that provides ground in park. I hooked the output from the Smartsiren to the common pin, and the NC pin to the lightbar mode/wig wag wire. When wiring was complete and I went to test it out, the starter would engage when turning on the slide switch to mode 1, thus enabling 12 volts to the relay. After testing the relays I was using, I noticed that 12+ was showing on the ground side as well. I opened up the relay, and realized that it had a feedback suppressor diode between the ground and positive pins. I removed the diode, thinking this was for sure the problem... Nope, the starter still cranked when the slide switch came on.
Am I missing something? Should positive be showing on the ground side of my relay with a multimeter? It makes since to me that the Crown Vic will start when 12+ is applied to fuse 1, but using pin 1 to provide a ground to my relay, should not being sending 12 volts back to the fuse...
Am I missing something? Should positive be showing on the ground side of my relay with a multimeter? It makes since to me that the Crown Vic will start when 12+ is applied to fuse 1, but using pin 1 to provide a ground to my relay, should not being sending 12 volts back to the fuse...