Now if the above does not help, and the Crutchfield unit seems to be OK. Either replacing the dash radio and console with the OEM version for that year if its possible - or you may have another issue with a simple fuse either pulled or is blown.
Care to go down a rabbit hole?
It's not far and it won't make you late.
You just have to know how the Radio was wired in, check those fuses, and there are others that affect ABS braking that when blown or pulled by a users actions, will affect the TCS light and it's operation.
If you are comfortable with the TCS (Traction Control System) being off, then you have nothing to worry about except when you sell it or you have an accident - you might need to explain why this was done. Else the Traction Control System is supposedly passive, but it's controlled by ABS, which, by law, works all the time, the TCS is just there to help in skids and loss-of-control moments.
It's when you pull the ABS fuse, that is where you may get into trouble. There are several systems that handle the ABS braking and are fused separately and power the ABS system as part of the redundancy. TCS is just one aspect of the ABS system that allows and it's programmed for, independent control of a wheel it thinks is spinning, not spinning as the same rate, or the vehicle is in a Yaw, pitch and rotation moment, thru the wheel sensors and SRS motion-sensor system as detected.
So the TCS responds to that input and tells the system what to do and (
in it's programming) how to fix it. With several solutions - up to and including throttle off - so that means, in it's thinking - in the days of old, the ABS system was designed that you should have the brakes on and you're steering input is all that is left for you to handle the skid - the TCS tries to keep all the wheels rotating the same speed - if your moving forward and still on the throttle, more than being in a slide-to-slide (fishtail) or in a spin by using those sensors as senses. Typical older-method of using these sensors makes ABS dumb compared to this - so think of the TCS as an evolution of the ABS system into a more advanced form of braking - it's handling the wheel it thinks it's in, as if it was in a skid - loss of control moment.
However, it also can control power being applied to the pavement - so it also tries to affect the throttle. Reducing the power being applied to the drive wheels - slowing it down to help you regain control. OR if your stopped - preventing you from going into a skid as you start to move, because the wheels are not all moving equally.
It applies the TCS controls until you regain forward motion and speed - then it releases so you can drive normally - as if you're out of danger.
(By it's thinking) This action, For some people, this puts them in more of a dangerous condition of panic for it can make matters worse if you know what you're supposed to do. This becomes a training issue - for if you're used to being in control of a vehicle and know how to control it in any form of a skid - the vehicle's reaction in trying to take over the operation when you're not ready or anticipating it to act one way and it goes in another - can put you in a crash due to that reaction - caused by inputs on both parties. (You, using your senses and the Vehicle using it's sensors)
However, with TCS on, the vehcile is fighting you in your effort of controlling it (your vehicle) because it's trying to control something that you're doing and it's not releasing the control for you to complete the action. This is one of the many reasons why Traction Control toggle on or off is still offered - even in the Fiesta - but someone pulled a fuse or that fuse blew due to the radio being installed - the system is pernamently disabled so that light on the dash is on - it's turned on by the systems it controls or uses - it's no longer talking to them.
The only reason why this is being mentioned is that many a sport enthusiast like to be in control of their vehicle - so take it or leave it - it may just be caused by a blown fuse they used to get power from to handle the Radio or a pulled fuse by a user that owned this vehicle before you got it and it's reflected on your dashboard showing you a system has been disabled.
