Temp gauge cold and then heat turns not so hot

There's a blockage some were as when ur driving the rpm is high so pressure is pushing hot water through when idling very low pressure u need to use strong flushing .agent and flush out your system also revirse flush if still doing it after this it will b ur main rad needs re coring not heater

Could be low on freon, have a pro check it out unless you have the proper gauges. Or could be the low pressure switch is not working. System must be tested for leaks first then pressure checked. DO NOT just add more freon from a can you could damage the compressor or parts of the a.c.

Air can be purged. While your engine is cool remove radiator and reservoir caps. Place funnel in radiator. Turn heat to the highest position and start vehicle. Add coolant to radiator as needed while vehicle warms up. You should see bubbles coming out of radiator. Fill reservoir to between cold and hot fill lines. Replace caps when bubbling stops but before coolant temperature reaches normal operating temperature. Never remove the radiator cap until engine has fully cooled down.

Your cooling fans may never turn off until the engine temp cools down enough. Also if your A/C switch (if equiped) is on the fan should stay on. The defrost position also turns the A/C on as well (helps to defrost windows faster) so that would turn the fan on.

Sounds Like A Problem With your thermostat. Good Luck

yes that means the thermostat is stuck open or you are low on coolant, check level first.

sounds like your thermostat is stuck open, if its takes a very long time for the engine to warm up and you get nothing but cold air from your heat then thats the first place i would start.

That wire you are unplugging is pinched and being shorted to ground ! You need to trace that wire until you find it . Also if anyone has done any repairs recently you may want to start looking in that area .

maybe...cuz the blend door may be not opening or closeing all the way

EITHER THE THERMOSTAT OR U ARE REALLY LOW ON COOLANT.