Speedometer not working the transmission is good nothing wrong

The transmission is good nothing wrong, had it flush etc. The light for the it came on and doing funny things, so I change sensor, light goes off. Now speedometer,
tachometer and mileage does not work! But if the car set in the sun or I take a long road trip the light comes back on and everything starts working, lol. It seems no one from the Ford service to local mechanic wants to pull the dash out put another speedometer and odometer in it. My question is, there has to be a better way than doing this. Where I don`t have to take out a loan to have this done or just say the hell with it and write down the miles I go and change the oil when its time to. Thank if you can help. David