There are only two reasons why you would experience what you are getting. One, the receptacles are not 12VDC and reverse polarity. I believe Doug has answered the reverse polarity issue which is more common than you think. Rarely will you find them wired with a 120VDC circuit. The plugs simply screw out and they're pretty easy to get to. Hold the outside part and unscrew the inside part. Use a meter to check voltage. Since you're experiencing the same issue with all three, it's in the wiring. If someone wired one wrong they wired all three wrong. Easy and cheap fix...Dennis
