Relay wiring

Anyone good with wiring relays. I got a spdt relay I want to wire up. I know how to wire it but want to see if can wire it differently. I know current flows from terminal 30 to 87. But I want to wire it so current flows from 87 to 30. That way I can wire 30 to the one point with 2 different sources. 87 will be power and 87a will be a ground. I'm using it for my wiper motor for the park function since I'm going to a momentary push button with a wipe module to control the high low speed