Friday, September 26, 2014
The Borg Warner S550 brake light switch (from Advance Auto Parts) is dead, no brake lights with any amount of pedal pressure, slightly less than two months 5,000 miles.

We opened the failed Borg Warner switch with a grinder to disclose the failure mode and the design-manufacturing deficiency. The contact plate is steel with a thin copper (or maybe cadmium) flash plating. It didn't take long to burn away the flash plating, after which the steel plate will corrode rapidly. Lots of driving in 60 days, 5000 miles, may have done 1000 to 3000 operation cycles on this switch. Since my trailer lights are LED's, total current for this switch is just 4-amps. A copper contact disc would be perhaps $0.02 worth of material. I can't imagine how much cost they thought they were saving by using the plated steel disc.