I don’t think I have ever seen this much corrosion without any drivability issues. I was diagnosing an aux. cooling fan issue the other day and had the headlight removed to gain access to the resistor. While I was there I noticed the plastic cover was loose and not correctly latched over the coil. So I repositioned it and in doing so I noticed a white powder on the frame rail. I removed the boot and this is what is discovered. Given the right weather conditions I’m sure this would have reared its ugly head.