Well, its back and all working great. Below is the full analysis from Ford service - some of which doesn't totally add up. The blown fuses and non-working lights were not an issue initially (I had all lights, blinkers, brake lights - but it is true that when I took the multimeter to it on Saturday, I was not getting reading - so maybe it just all went downhill in a short period. The other odd thing was the replacement of the trailer plug - indicating it was broken with corrosion. They had to replace that after replacing the controller. Here's the diag:
No lights to trailer. Found no DTC for BTC. Found 3 fuses f82, f58, f31 and one relay (#6 and 1 blown fuse. All lights working. TBM shows trailer not connected. Went symptom test. Found TBC module not sending correct voltages to plug.. Replaced TBM. Truck is currently working properly at this time. Checked trailer malfunction in the plug. Disassembly of plug found broken and corrosion. Need to replace plug in trailer. Installed new trailer plug. Now system is working properly.
