bovine
1974 Cherokee 140
The dimming knob on our Cherokee 140's instrument lights had been operating poorly. The observed behavior was that the lights seemed to go from bright to dark suddenly as you rolled the knob, so setting it for maximum brightness required some careful positioning.
We ended up removing the old dimmer potentiometer and replacing it with a working one from salvage (P/N 67436-4), but I was curious about what caused the old one to fail so I opened it up...
As you can see in the attached image (or the higher resolution version), the wrapped wires near the low end and the high end are worn/broken completely. The few remaining wires on the high-end show were the narrow area where we could get maximum brightness.
We ended up removing the old dimmer potentiometer and replacing it with a working one from salvage (P/N 67436-4), but I was curious about what caused the old one to fail so I opened it up...
As you can see in the attached image (or the higher resolution version), the wrapped wires near the low end and the high end are worn/broken completely. The few remaining wires on the high-end show were the narrow area where we could get maximum brightness.