Question about 2000 GMC New Sierra 1500

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2000 GMC Sierra 5.3L. Heater is stuck on full heat. It is not responding when I turn the dial to make colder.

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Sounds like you have a bad actuator motor that is what moves the door in heater box to change from hot to cold

Posted on Jan 30, 2010


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Heater wont blow hotair

Hi Dennis, I'm glad to help!

Dennis, there are only 4 possibilities when you have NO Heat. (1) Your are low on coolant. Check your Radiator and see if it is full. (2) The heater core is clogged. First run the engine until it reaches operating temperature with your heater turned on, then grab one heater hose and compare it to the other. If it's clogged one will be extremely hot and the other somewhat warm. If it's not clogged both will be extremely hot. (3) You could have a blend door problem. Which means the door could be stuck in the colder side. It also could be broken or the motor is bad. (4) The control head could be bad and not actuating the door. If you like call me 314-374-5218 I'm in St Peters. Hope this helps and have an awesome day Dennis.

Jan 23, 2013 | 2000 GMC Sierra

1 Answer

Truck gets warm no heat in cab new heater core new filters

thermostat stuck or heater control valve may have air in the system too

Jan 15, 2011 | 2000 GMC New Sierra 1500

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I have no heat in my 2000 chevrolet Z71 p/u, even after changing thermostat. When I turn temp indicator dial ther is no change in air coming out of vents.

Please see my tip at . These are generic instructions. If you get stuck or need specific instructions for your car, please get back to me with model, year and engine info.

Dec 28, 2010 | 2003 GMC Sierra 1500

1 Answer

Very little heat from heater truck can be running for long time very little heat comes out

You HVAC unit is not getting the heat from your engine coolant. A valve is stuck or there is blockage in the heat exchanger core. I'm assuming you fan and vent divertors/Controls are working correctly. Does AC work?

Jun 13, 2010 | 2000 GMC Sierra

1 Answer

At idle, Heater Core Return Line is flowing only

two things--first replace your cabin air filter.second reverse flush your heater core with a garden hose and that should remove the build up of material in your heater core and restore the flow,hope this helps

Oct 21, 2009 | 2000 GMC Sierra

2 Answers

Heat will stay on high until turn engine off and back on

check dial switch, check valve that lets water run through heater core

Aug 23, 2009 | 2000 GMC New Sierra 1500

2 Answers

Heater stuck on full heat

Did you ever find a solution to this problem? My 2001 Sierra does the same thing; if I turn on the heat to full hot it remains stuck for a while. Sometimes it sticks for a couple of minutes, other times it sticks for a couple of days. As long as I don't turn it fully to hot though, it doesn't stick. It has gotten worse recently.

Feb 28, 2009 | 2001 GMC Sierra Crew Cab

1 Answer

2000 gmc sierra 5.3l heater does not get hot

After replacing the thermostat I pulled the heater hoses off and blew air through the heater core at firewall. Can only blow in left side as directional valves will prevent opposite. Chunks of stuff came out with coolant. I then put a piece of hose on the left side and shot water through until it came out clear.
Put it all back together and heat works fine.

Dec 31, 2008 | 2000 GMC New Sierra 1500

1 Answer

Heater in 200 gmc sierra is not workinmg

make sure antifreeze is full. run engine 10 min. verify engine is around 195 degrees. if not, try replacing thermostat. if it is running at 195, then maybe heater core problem or heater control not functioning properly

Nov 16, 2008 | 2000 GMC New Sierra 1500

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