[Marco71Z]

I bought a 74 260z and I finally got it running and I take it around the block and poof the dash starts smoking and a melted wire falls on my leg from under the Steering column, car turns off. Here are some pics I noticed a wire from behind the ignition switch that I recently replaced was burnt out as well. Any ideas on where to start?? Thanks.

 

[8tzx]

For the wire to "melt", excessive electrical current was flowing thru the wire. Excessive current flow could be caused by a short circuit. I would first locate a wiring diagram and determine what circuit was impacted. I would then check the fuse for the circuit and verify that it is the correct rating. Fuses are rated to prevent current from flowing at a level higher than the ampacity of the wire. If a higher rated fuse was used, it allowed current to flow thru the conductor at a level greater than what the wire was rated.

 

[Dave M]

did you do anything as far was modifying the wiring? do you have the factory fuse links installed under the box mounted on the fender wall. welcome to the world of old Zs and prior wiring hacks. One more thing are you completely stock on all things electrical (no "upgrades") I can see the aftermarket AC control switch, pretty sure that was the add on model that could have been done by a dealer. I would look for ANY hack into the oe harness that smoked. Does the ammeter work and was it reading normal on the drive around the block.

 

[Marco71Z]

did you do anything as far was modifying the wiring? do you have the factory fuse links installed under the box mounted on the fender wall. welcome to the world of old Zs and prior wiring hacks. One more thing are you completely stock on all things electrical (no "upgrades") I can see the aftermarket AC control switch, pretty sure that was the add on model that could have been done by a dealer. I would look for ANY hack into the oe harness that smoked. Does the ammeter work and was it reading normal on the drive around the block.

Looks like there was an aftermarket alarm installed but that’s all I see as far as add ons, the thicker fusible link was a little loose o has to play with the connection for there to be power inside the car. And the insulation around the wire was degraded so since then I bought new fuseable links.

 

[Dave M]

talking about the fuse links under the plastic box correct?

 

[Marco71Z]

talking about the fuse links under the plastic box correct?

I think I figured it out the thicker constant power on the ignition switch harness was kinda exposed and it was rubbing on the accessories wire on the ignition switch harness and heater up the wire. The wire that melted was the alarm wire that was spliced into the accessories wire, I separated everything re wrapped everything and car turns on and seems to be running fine, thanks for for the replies! I’ll update if something else happens.