Can I use a S.P.D.T. relay to turn on a N.O.Pressure sw. when a N.C vaccum sw turns off.What I have is a 700r4 trans.,the 4th. gear pressure sw. & soli.valve are n.o. & grounded to the case.Im using a ome vac.sw. that is n.c.The vac.sw. turns it self off when engine vac. gets to7.0 ins. of vac. that when I need the relay to send voltage to the pressure sw.In other words the relay sees that the vac.sw. has turned off and now switchs on the pressure sw.Can one relay do this or is it going to take two.This is the relay w/ 87 & 87a.Im just not seeing this in my head.