You were correct, Grumpy, they are not in series. I either didn't notice the first one blow or both of them blew at the same time. I replaced both with a pair of 1156 LEDs (280 lumen)...the lumen output isn't quite as bright as the incandescents but they do the job.
2013 26BH ghetto model w/ 4 plain rims and some rust
2001 Silverado 2500HD 6.0 gasser
I have a fever...and the only cure is more camping!