Cadillac Repair: blown fuse IGN 1 engine compartment fuse block, brake master cylinder, fuse block

Question
1994 Cad DeVille 4.9 engine. When I shift from Park to Reverse, fuse, designated IGN 1 10 amp engine compartment fuse block, blows. Consequently no A/C, cornering lights, backup lights, fuel gage error,air bag readiness light and other status lights,and other things on this circuit. Remaining in Reverse, after replacing fuse, everything returns to normal. What might cause this?

Answer
Even the backup lights are illuminated ?.

You most likely have a short in the NEUTRAL STARTER SAFETY SWITCH or the electrical harness with all the wires in it are laying against the shift mechanism and is being temporarily shorted out when you move the shift linkage at the transmission.

If you look just below the brake master cylinder and have someone shift the transmission thru the various gears you will see the shifter cable moving on top of the transmission. Check to see if any wires are being rubbed against the shift mechanism.