Purchase a laminated color copy from cl***iccarwiring.com for about $20.00 off the net. The have 2 sizes for most vehicles. Best thing you can do for trouble shooting.
When I got my 55, the back up lights didn't work. Chased my tail for quite a while till somebody said the 55 factory back up lights didn't work UNLESS the tail lights were on. I guess Ford figured you didn't need them unless it was dark enough to turn on the headlights. Just sayin....... Mark