[EagleNova]

I'm having a problem with the heater in my 2014 Patriot North Edition. I recently dropped it off at the dealer to have work on replacing an OCR sensor. After I got it back, the heater only blows cold air. I confronted the service manager who denied that they had anything to do with the heater failure. The heater blows cold air through all the vents when the temperature knob is set to hot. If the heater core had failed, would there be any sign of coolant leak on the cab floor? Where would I find the relay for the heater? After the jeep is turned off, there is a mechanical sound coming from behind the glove box, so I assume that the blend doors are functioning. Winter comes early to this part of the world. I won't be bringing it back to the dealer ever again. Need help. thanks in advance.

 

[Pepe]

Hi EagleNova,

To discard a heater core failure, do the following: after running the engine for some time (temp gauge needle near midpoint), open the hood and look for 2 black hoses located exactly behind the engine's upper right corner going through the firewall. Carefully touch both hoses. If they feel hot, that definitely is not a problem related to the heater core.

The mechanical sound you hear (glove box side) comes from the mode door actuator, which controls air flow from vents. Nothing to do with hot/cold air. If no mechanical sound from behind the steering wheel side, you probably have a bad blend-air door.

Turn ignition on and take a look below the steering wheel (upwards to gas pedal) and search for a black motor unit with a white arm and a big white gear. That's the blend-air door actuator. Now, turn on the A/C and move the temp knob. If the mechanism doesn't move while you change temp, it has stuck on 'cold' position. Gently move the arm and/or gear to free it.

You should now have hot air again and A/C should react to temp changes from the knob.

 

[O'DubhGhaill]

Hi EagleNova,

To discard a heater core failure, do the following: after running the engine for some time (temp gauge needle near midpoint), open the hood and look for 2 black hoses located exactly behind the engine's upper right corner going through the firewall. Carefully touch both hoses. If they feel hot, that definitely is not a problem related to the heater core.

The mechanical sound you hear (glove box side) comes from the mode door actuator, which controls air flow from vents. Nothing to do with hot/cold air. If no mechanical sound from behind the steering wheel side, you probably have a bad blend-air door.

Turn ignition on and take a look below the steering wheel (upwards to gas pedal) and search for a black motor unit with a white arm and a big white gear. That's the blend-air door actuator. Now, turn on the A/C and move the temp knob. If the mechanism doesn't move while you change temp, it has stuck on 'cold' position. Gently move the arm and/or gear to free it.

You should now have hot air again and A/C should react to temp changes from the knob.

Excellent! I was experiencing the same problem and this fixed it! Can't imagine how much it would have cost to have this diagnosed.... Thank you!

 

[Nicky]

Yeah, thanks