Hi, I had to revert this due to the way you mapped this.
Can you tell us what SLC is and where is it located as I can't locate it on the map? Which default routing are you referring to? The service road is gated where it joins Soldiers Road and sign states private property and land is or leads to Rivercrest Christian College so I am not surprised a navigation app does not route down the road when approaching from Ferdinand Drive.
But if SLC is mapped perhaps some apps may route to it along the service road you altered.