Paul,
The step/grab handle lights & porch light are on different circuits.
The porch light and map lights are on the same fused circuit, it is labeled MAP LTS.
Do your map lights work? If not, perform the following.
Turn the ignition to run and the porch light on.
Front Run Bay.
PCB14, check the 15-amp fuse labeled MAP LTS, the associated red LED should be illuminated (if the ignition is in the run position), if the LED is not illuminated fuse is probably bad. If the LED is illuminated check the connector on the circuit board.
If the porch light still doesn't work check the green LED on PCB1 labeled RELAY OK PORCH LT. If the LED is not illuminated, you may have a bad relay on PCB1. If the LED is illuminated check the connectors on the circuit board.
Please report back your findings.
-Scott