2006 Pontiac grand prix heater not working. blower works fine had a new thermostat installed and the heater core flushed out. with no luck. I can hear the diverter valve working as I turn from cold to hot. Is there a heat control valve on the car and where would that be located? Would there be something else I can check?

SOURCE: 2006 pontiac grand prix vary little or no heat

Are you sure you got all the air out of the cooling system? Air pockets are very common problem when you do any work to the cooling system. An air pocket will do what you discribe.

SOURCE: I have a 1999 pontiac grand prix and the heater

is the temp gauge working and showing the engine is warmed up? also check the heater hoses in the engine compartment ensure both are at the same or close to the same temp. if they are not could have plugged heater core. try flushing. possible blend door could be stuck.

Testimonial: "I had already flushed the heater core after further reshearch and you were dead on. 10 second flush and now I have heat."

Jeffrey Turcotte

• 8991 Answers
• Posted on Sep 24, 2010

SOURCE: friends car(2001 pontiac grand prix)

yes, but it's designed to drive the air out as long as you open the cap and run it until it's hot, keeping the radiator full. Eventually the air will come out and heater hoses should get coolant.

Duane Wong

• 6826 Answers
• Posted on Nov 19, 2010

SOURCE: 2006 grand prix heater only blows cold air. both

Sounds like the temperature blend door actuator may be bad or the vacuum hose to it is disconnected.

Poor Heater System Performance CAUTION
Check all fluid levels and adjust as needed, before operating vehicle for extended periods at idle.

1. Start the engine.
2. Idle the engine until the thermostat opens (upper radiator hose will be hot) Is the engine at normal operating temperature (approx. 200° F)? If yes, go to the next step. If no, go to step 16.
3. Set the mode selector to FLOOR mode.
4. Set the heater control selector to the warmest temperature setting.
5. Set the blower speed the lowest setting.
6. Carefully feel the inlet and outlet heater hoses at the heater core. Is the inlet heater hose significantly hotter than the outlet heater hose? If yes, go to step 14. If no, go to the next step.
7. Set the mode selector to PANEL mode.
8. Select the maximum blower speed.
9. Select the warmest temperature setting.
10. Place a thermometer into the center I/P PANEL air outlet and affix a second thermometer to the heater core outlet heater hose.
11. Record the temperature at the center I/P PANEL air outlet and at the heater core outlet heater hose. Are the two temperature readings about equal? If yes, go to the next step. If no, go to step 13.
12. Inspect and repair the cowl, cowl area, recirculation door, and the HVAC evaporator/heater core case for cold air leaks. Repair any problems found, go to step 17.
13. Inspect the temperature door operation. Repair any problems found, go to step 17.
14. Turn OFF the engine. Back-flush the heater core. Start the engine. Select the FLOOR mode and the lowest blower speed. Select the warmest temperature setting. Feel the temperature of the inlet and outlet heater hoses at the heater core. Is the inlet heater hose feel significantly hotter than the outlet heater hose? If yes, go to the next step. If no, go to step 17.
15. Replace the heater core. When the repair is completed, go to step 17.
16. Check for low engine temperature problems, Repair or replace as needed, go to step 17.
17. Operate the system in order to verify the repair. If the system operates properly, the repair is complete. If the heater still does not work properly, repeat the entire procedure.

SOURCE: i have a 2006 pontiac grand prix 3.8l my heat only blow cold aair I checked the thermostat and the heart inlet hose is hot but the outlet hose is luke war what could this be maybe clogged heater core.

Ok fellow 2006 Grand Prix owners!! By trial and error, I went through the process of elimination because my car would over heat and had no heat inside. After changing the thermostat, I had to replace the water pump. However, after you do this, you need to open the inlet hose bleeder and let the air out a few times. This solved my issue of overheating and I now have great heat!!!