Make it simple.
1. Go to the 4 wire quick connect at the step
2. Large Red wire should have 12 volts all the time. IF NOT, then trace to where that wire is indeed fused
3. White wire should have 12 volts all the time. IF NOT, find the inside ON/OFF step switch and make sure it is turned ON, IF NO 12 volt power if that switch is OFF or ON, trace back to find the blown fuse.
4. The YELLOW wire is ONLY HOT when the Engine is ON and is NOT NEEDED for standard step operation
5. The BROWN wire comes from the Step magnet or pin switch in the entry door frame. IF you have 12 volts on the White and RED, jump that brown wire to ground and release, if the steps do not function, then the Step magnetic/pin switch wiring has a problem.
6. Starting with this checklist will narrow down what to find and save time. Doug
PS. HOW did you check the various fuses you found?
