77 engine and tranny (?). The neutral safety switch has three wires. A purple with black tracer, a black with yellow tracer and a white. I think two are for the backup lights, could be wrong. Which one is the nss?

 

One is going to be power, one is going to be for park/neutral, and the other will be for backup lights. What isn't working?

 

1 should be ground and 1 should go to the reverse lights and one should go to the starter relay. best to look at the starter relay to see which wire goes to it. then the other 2 should be ground or reverse lights

 

The brake light fuse blows when the shifter goes to neutral. It’s an automatic. Wondering if the problem is tied to the nss somehow.

 

You have a short somewhere. Think I would start by looking at the harnesses near the shift linkage, make sure the linkage isn't crimping on of 'em.

 

have you tried disconnecting the NSS and then doing what doing what you do to cause to get the fuse to blow? i would start there and then start pulling bulbs out of the tail lights till fuses stop popping. if fuses still pop may be an issue with a connector somewhere.

 

Haven’t pulled the nss yet but that’s a good idea. It has LED bulbs and I pulled them and swapped in regular 1157s but the fuse still blew.

 

Oh here we go! I pull the nss, put the ignition switch in on position but did not start the truck. Foot on brake and move the shifter to neutral and blew the fuse. BUT! I can here it arcing in the steering column! Now we know where the problem is.
l’m leaving in the morning for the weekend so this is on hold until next week. Then we start digging.

 

may want to disconnect the battery if you have an electrical issue that is causing arcing. does the truck have tilt steering?

 

No tilt steering. Battery is disconnected.