Issue: Ignition Wire Overheating and Melting Connector

[Chargerx3]

This winter i was dailying Mad Max. Its my 90 V6 4x4 that I turned into a 3.8L Mivec build about 8 years ago. Well, while driving the one day i noticed a faint smell of melting plastic. Turns out it was the wire going to the ignition switch that meets at the base of the steering column. I took it apart and cleaned it and it never quite got that bad again, but it can get hot to the touch.

I swapped out the ignition switch this week and the problem didn't go away. I'm wondering where this solid black line leads and if anyone else has had this problem?

You can see some of the melting here. Far right lead.




https://imgur.com/6fArLr0

Sorry links come in large.

[SubGothius]

Prolly excessive resistance and/or current draw in some circuit that goes thru that wire. That yellow side tap with the red wires seems suspect, might wanna have that just trigger a relay instead, which in turn switches power direct from the battery (+) terminal.

[Chargerx3]

Thanks for responding. That wire goes the the AFR gauge. I can pull it for testing purposes. I did notice that the IGN fusable link (wires on drivers fender) got warm as well. Do you think its a poor ground, or more electricity coming into the circuit?

Not sure what would cause this. Also no issues when just in "On" position and not running.

[SubGothius]

Hm, strange about the ON position behaving different with the engine running vs. not. Only electrical differences I can think of between those conditions would be the coil firing, the alternator running, and gauge signals (that AFR as well as temp/voltage/oil-pressure lights/gauges).

Maybe a bad/failing voltage regulator allowing the alternator to output excessive voltage?

[Chargerx3]

Hm, strange about the ON position behaving different with the engine running vs. not. Only electrical differences I can think of between those conditions would be the coil firing, the alternator running, and gauge signals (that AFR as well as temp/voltage/oil-pressure lights/gauges).

Maybe a bad/failing voltage regulator allowing the alternator to output excessive voltage?

Voltage at battery reads 14.44V and 13.69V at the ignition switch. That seems about normal right?

[1600cc]

Does the wideband 02 sensor for your AFR gauge get power from that gauge and therefore that wire? The sensor has a heater element and draws significant power

[Chargerx3]

Good point. I'm certain its only the gauge, but good point. Im out of town for the next little bit but ill look into it some more.