My heater worked fine on the way to work this morning... After work though, it only wanted to blow cold air. It only gets warm if I set the temp to high.


Did anyone here experience the same thing?

 

Check the aux pump, they are known to go out. If dead you will not have heat at idle or low speed, should have heat above 40mph....maybe.

 

Can you tell me where I can find the aux pump?

TIA

 

Bottom right front fender area. It's the pump with two 5/8" and 1 1/4" hoses and one electrical connector on the other end. Can't miss it as it sits close to the exhaust manifold and alternator.

 

Could be the duovalve. It's more common for them to stick open, but they could stick in the closed position. You can use the AC diagnostics to check the heater core temperatures. With the heater on, the left and right heater cores (#3 and #4 in the display), should be pretty close to the engine coolant temperature (#6 in the display). The diagnostics should only take a minute to check on a car that's warmed up.

 

Hi Marcus,

Here are the codes

1 - 100
2 - 74
3 - 152
4 - 150
5 - 42
6 - 185
7 - 10
8 - 107

I have heat only when I use the defrost button. The other vents only get warm even if I set temp to high. Any ideas?

Thanks

 

Your heater cores are over 150, so you should feel heat. Set the temperature to max - not the blower, just the temperature and see if heat comes out. I seem to remember an in car temperature sensor that's been known to go on the fritz.

 

Temp settings to high, blower on low... I can feel a little heat coming from the vents this morning while I'm driving. Once I stop, the heat stops. If I turn the blower to high with the temp set to high, cool air comes out. If I set the temp to 75, cool air comes out when I'm driving or have the blower on.

Where can I find the incar temp sensor?

Also, I found what I believe is the outside temp sensor. Is it supposed to go into this hole? Seems like a tight fit....

 

And the defrost can still blow HOT air if I needed... the other vents just blow warm or cool air.

 

I just finished cleaning the incar temp sensor.......nothing...


Anything else look at?

 

Code #1 is 100. Unless it's truly 100 degrees in the car, the in-car temperature sensor is giving a false reading.

 

I MAY BE WAY OFF BASE HERE BUT BE "SURE" ENGINE IS FULL ON COOLANT. IF IT IS LOW, CIRCULATION WILL STOP AND COOLANT TEMP WILL BE ERRATTIC.