[HO455]

Spent most of the afternoon with the repair of the ignition switch. First off is picture of the bad switch disassembled. I would like to find a OE switch to disassemble for comparison of the contacts.
I have to say I didn't find a smoking gun that I can point to as the problem. I concentrated on the solenoid wiring to start. Following LockDocs lead I did a ohm meter test on the neutral safety switch by removing the purple connector from the switch and hooking my meter to the switch. By moving the gear selector through the all the positions several dozen times while watching the meter. For the most part the meter would read .05 ohms when in park or neutral, but there was a couple of times the reading would be 4 to 8 ohms. So I removed the switch and disassembled it. The photos (#2 & 3) show some wear on the slider and some arc wear on the contacts for the back up lights. In addition the both of the tabs the backup connector hooks to show some heat discoloration from some past issue.
I filed the slider flat and cleaned and soldered the back up light contacts to remove the arc damaged spots. Those spots are probably all/part of the reason that sometimes I have to jiggle the shifter to get the backup lights to come on. I buffed the all contacts with a brass wire wheel in my Dremel, greased the slider, and reassembled. Testing after reassembly showed consistent readings and smooth operation.
Ohm meter testing of the rest of the solenoid wiring did not revel any other issues.
I then moved to replacing the melted connector body on the harness. I found Napa carries a replacement pigtail for $18.00. (Photo 4) A bit steep as only needed the plastic body but I didn't find any other option. I do plan on saving the leads for other projects. One item of note is the wires that come with the replacement pigtail are noticeably undersized compared to the factory wiring. (Photo 5) The red, purple, and pink factory wires next to the wires from the pigtail leads.
After the connector was reassembled and the switch plugged in I did amp load testing on each lead n the connector. I found the total load on the switch to be about 23/25 amps with everything turned on in run. The large brown lead as about 12/13 amps and the pink lead was 8/10 amps. The solenoid circuit was 12/15 amps.
I forgot to post that the rest of the brown wires all had 5 amps or less.
These readings are not extremely accurate as they are on the lower range of my amp clamp attachment. (It is rated for 4 to 400 amps.) But I am confident that there isn't an overload condition for the switch.
One other thing I looked at was how the Packard connectors fit the tabs on the switch. They all looked good except the one for the solenoid. The part of the connector in the middle had lost its spring tension so I replaced it. The connector showed no sign of overheating or arcing so it may not have been part of the problem.
After the plug was installed on the switch I carefully inspected each of the Packard connectors with a magnifying glass to be sure they have slid over the switch tabs properly. Low and behold one of them has completely missed the tab and is just sittng next to the tab in the connector body. To get all the connectors to install properly I bent each tab slightly so it was biased toward the Packard connector. I was then able to get the connector installed properly. This problem may have contributed to the failure, but I have no proof.