Ahh yes, another Ford garage fire. I looked up the part and it looks similar to a mid '90s Escort ignition switch. They have four plastic pins that ride on a cam wheel with ramps to push them up and down. When the switch contacts overheat, those pins melt. The ones that normally hold a switch open, (off), can shrink and fail to do that so some things may continue working when they should be off. The melted plastic from one of those pins can also run in between a pair of contacts and block them from turning on. I've seen both conditions in the same switch. The first problem was the engine would not turn off. After playing with the switch to get the engine to stop, the second problem was the starter wouldn't engage. Both problems were solved with a new switch.
Look at the light switch for overheated terminals in the connector. If there are, at least two wires will also be hardened for about four inches. That part should cut off and new pieces spliced in. After the switch is replaced, cut the overheated terminals out of the connector body and cut away all the melted plastic. Reinstall the connector to the new switch, then install universal crimp-on terminals to the new wires, but solder them too for a better, more solid connection. Insert those individually into the switch.
The splices for the four or five inches of new wires should be soldered, then sealed with heat-shrink tubing; never electrical tape. Tape will unravel into a gooey mess on a hot day and leave the bare wires exposed.
The same repair can be done to he ignition switch connector if there are overheated terminals in it.
I don't think any circuits can short together so I don't have an explanation for the blown fuse
Friday, July 29th, 2011 AT 3:50 AM