2005 explorer trigger for remote start

Hi all, I installed an Ultra Start remote starter in a 2005 Ford Explorer 4x4. It's the type that uses the original remote door unlock to trigger it. I used the (-) unlock wire and that worked fine if I use the unlock button on the door but it doesn't work when I use the FOB. I don't think it's enough of a change in signal. Any suggestion on how to correct this or another source. I can use a (-) or (+) Thanks Wizard

test your unlock wire...when pressing the fob, bet you dont get a negative. trying using the positive unlock motor wire with a relay to make it negative...

Mike M2 wrote: You need to use the positive instead and go to the drivers door motor wire. I would also suggest using the lock leg instead of unlock so the truck would be locked after you RS it.....

this

Thanks guys, that worked perfect.