How do you fix a 2011 Impala bad mph light?

GM products are so weird these days anything is possible. I would not have believed that the infotainment system going out would cause the HVAC, the turn signal sound and the battery draw to increase to the point of killing the battery in a few days to happen either. But it did, plus you can’t get any parts to fix it from GM. Hopefully you can find a service manual on your vehicle that has flow charts and can trace down the circuit and see if it has load sensing for the lamps, if it doesn’t then you will probably be okay.

Answer not posting

Instead of just asking the same question again, why don't you think about thee problem and find a better way to form your question so people will understand what you're saying. The previous answers you got were well done. If that wasn't to your point, or you don't know how to speak "car," have a mechanic look at the problem. Remember: HE CAN ACTUALLY SEE THE CAR.