48loadmasterguy,
I don't know if this is accurate, but a wiring diagram I looked at shows the dash lights coming off a common light switch terminal with the taillight. If this is true, it would appear that if it were a defective switch, neither dash lights or taillights would work when switched on...if the taillight does work, then the problem would be bulbs or a poor ground for the dash lights themselves. This isn't the brake light, just the taillight.
Stuart
