I am blowing out bulbs on my trailer lights at an alarming rate. Every couple of weeks, one, or both are blown out. By "blown out" they are not merely burned out like I would expect, but both filiments are gone and the inside of the bulb is blue-grey. In some cases, a piece of the glass is broken out. I have an F250, pulling a Big-Tex 6.5X12 single axle trailer, with ramp end gate. I use the trailer to haul three mowers, and grass clippings. My travel is local, driving 50-80 miles per week. I work residential neighborhoods, so there is much stopping, turning, etc. The tail lights aren't used very much -- I'm usually home by dark. The fixtures are typical plastic housing, with a side light. The bulbs are 1157BP. Since April 1, I have replaced 6-8 of them. What is causing the problem? I started using an F250 nearly two years ago. Before that, I was using an F150, and I don't recall the problem. Also, I don't recall the problem until part way through the mowing season last year. The frequency of replacement has me concerned that something has gone wrong with a power surge, ground, or ???? Any thoughts?