My temperture gauge on the dash is reading as if my cars over hea

Sounds like you replace the temperature sending unit(for the gauge on dash) what you need to replace is the Temperature sensor for the computer (ECM)

If the engine really is not heating up, the thermostat could be stuck open. Or you could be low on coolant and the gauge is not reading correctly.
Or if the engine is warming up, the sensor for the gauge could be faulty.

Your heater core needs to be checked out. It may be clogged and needs to be replaced.

If the Temperature gauge is moving less than before, its your Thermostat. If the Engine Temperature is the same, then your heat control valve is not opening or a duct flap(called a door) is not moving under the dash.

Having a Bad thermostat will affect how controls on the engine work and when they work.

Defective coolant temperature sensor if it reads hot as soon as you start the engine. Check the wiring before replacing. The gauge itself can also be bad but not likely. The temperature sensor will look like this.

the temperture sensor is bad and the sensor is on the left or right side of the engine by the goose neck

temperture gauge is not working and dash sign comes on says turn off e/c e/c is on , but the temp gauge doesnt work

first of all check the radiator for leak or blockage. make sure the coolant is fresh. follow th eupper radiator hosr to the emgine block. there should be 3 bolts attached the themostat housing. take the themostat out and put it with hot water, maks sure the opens. the temperture sending unit should be directly under the themostat. msot likely the themostat is cause or the problem. unless the temperture gage is not reading correctly.

Most likely the heat sensor.
Ensure you replace the gauge sensor with the correct type to suit your gauge.
(dont confused it with the overtemp alarm switch sensor).
Check you've got the right sensor by shorting it out to frame/ground and observing the gauge movement.

First of all, it doesn't sound like your thermostat is working correctly to keep good hot/warm air coming , so I would change that, or have it changed for better heating inside. If you lift the hood & look in front of your radiator, On the engine side, you'll see a fan attached to, or in front of the radiator. It won't come on until the coolant temperature gauge gets up to proper operating temperature. Without getting in to too much detail, have your thermostat changed, and my guess is everything else will start working as it should, and whoever does the work, should know enough to check the fan operation when they do the thermostat.