reviving this thread, just bought myself an 05 V6 and also has the same problem. ABS and TC lights are on. Scanner did not register any codes.
I also noticed that the hand brake light is always on even of the hand brake is all the way down. Could a faulty switch cause these lights to turn on?
Yeah, if you remove your center console - or at least the part under the shifter, you will see a part of the wiring harness with a plug that goes to (or near) the e-brake mechanism. Take a look at the plug, unplug it, spray it with some electrical contact cleaner, and maker sure it is securely mounted and no wires are messed up. If that plug is malfunctioning, it would definitely light your ebrake light and may even cause your advance trac light to come on.
Look at the photos I posted in this thread for an idea of what Im talking about
2011 Mustang GT M6 3.31s
Matt HONEYCUTT Tune, Lethal Off-Road X, GT500 axlebacks, J&M LCAs, UPR UCA, Whiteline LCA relocation brackets, Eibach Pro-Kit Springs, Koni STR.T shocks/struts, GT500 strut mounts, SR Strut Tower Brace
Best 1/4 E/T (05/18/14 MIR - no tune, X-pipe, or UCA): 12.920 @ 109.40 mph (2.059 60ft)