One problem related to brake light on has been reported for the 2006 Ford F-250. The most recently reported issues are listed below.
Front brakes seized up when driving down road just as warranty was to expire. Contacted dealer after this had happened 4-5 times. Dealer replaced front calipers but was out of warranty. 4 months later had to replace both rear calipers for seizure problem. Ford dealer would not provide any compensation. Now 2 months later, check brake light is on.