I have had my mechanic replace the brake swwitch 3 times in 8 months..

Good morning Patty, If there a burning smell and the switch has had to be replaced three times I think there is probably going to be a bad connection at the switch. Too much resistance in that circuit (at the switch) causing the switch to burn out. I would guess that the switch connector will need to be replaced. I think there is a service bulletin that Ford published with the same symptoms and the repair was to replace the connector. We are a RepairPal "Top Shop" and we are located in Melbourne. Take a look at our profile and stop by or give us a call. I think you will be glad you did. Thanks and have a great day, Brin Assured Auto Works, Inc. 4451 Enterprise Court Suite N Melbourne, FL. 32934 321-610-7977