Burned pin in headlamp switch plug - 82 KZ750 LTD

Has anybody else run into this? One of the pins in the 9-pin connector feeding the headlamp switch has burned out causing the low beam to not function and the headlight warning light to stay on. It's the blue/yellow pin and it burned up on the reserve lighting unit side of the 9-pin connector




This connector seems marginal at BEST when it was brand new, add in 30+ years of oxidation and decay and no wonder it burned up. It's funny because the other connectors in this path are all big wide spade connectors. There is over 4A running through these tiny pins! I'm going to split out the blue/yellow, blue/orange, red/yellow and red/black wires into a weatherpack 4-pin connector to prevent the next wire from just burning up as well, but I was curious - has anybody else run into this problem or am I alone?

I repaired this last night - put in a 4-pin weatherpack connector and removed the red/yellow, red/black, blue/yellow, blue/orange wires from the 9pin lighting switch --> main harness connector. Now the lighting all works properly, though I am still seeing nearly 1.6V of drop between the battery and the headlamp. No wonder the headlamp is so dim! If I have any further troubles with the reserve lighting or light switch setup I'm just going to ditch the reserve lighting box and install a pair of relays driven directly from the switch to power the light (properly fused of course)

What is the wattage of the headlight you are using? I had a 6-pin connector overheat, although it didn't cause the light to stop working. I found it and replaced it when performing some other maintenance. In my case it was my own fault. I had run a 100w H4 bulb for more than a year, so in retrospect I'm not surprised it cooked the connector. Ed

There was a Philips brand 55/60W H4 bulb installed when the connector melted. I had been driving quite slowly in heavy traffic on a rather warm (25*C) day when the failure occurred.

Doing some quick back-of-the-hand math with a 1.6V drop in the harness/connectors and ~4A current for the bulb there is about 6.5W of heat being sunk into the harness and connectors right now. That gives me an uneasy feeling.

This type of thing will usually show up in the ignition switch or connectors. I'd check them too. Once a wire overheats, it has more resistance. I replaced a few wires this last time for that reason.
Steve

Right - next time I have the tank off and can reach all of the connections I'll try to localize the voltage drop and see if it is a single point causing the problem or more than one.