Intermittent Front AC - Burning Smell Outside - 2018 Exp. Max

[spencerfrazier]

The Front AC blows great and then it diminishes randomly throughout the day. Still blows cold but barely blows at all even on high / auto / whatever else you try. There is also a burning smell outside. I am thinking this is the blower motor going bad potentially or is there a resistor up front or only in the rear? Has anyone changed a blower motor on a 2018 Expedition?

Anyone have instructions to replace a blower motor for front AC?

 

[99WhiteC5Coupe]

The Front AC blows great and then it diminishes randomly throughout the day. Still blows cold but barely blows at all even on high / auto / whatever else you try. There is also a burning smell outside. I am thinking this is the blower motor going bad potentially or is there a resistor up front or only in the rear? Has anyone changed a blower motor on a 2018 Expedition?

Anyone have instructions to replace a blower motor for front AC?

The blower motor assembly and resister (controller) module is underneath the glove compartment. To access it, you may have to remove a hush-panel.

I would check the wiring connectors, as it sounds as though you have a poor connection or burnt connections.

Do not put this repair off, as if you are smelling a burning condition - you could experience a fire.

The resister module is held to the HVAC case with screws, and has a wiring connector. The blower motor assembly is held to the case with about 6-7 screws, and also has a wiring connector.

 

[spencerfrazier]

It is strange as I only smell it when I am outside the car. Seems like it is coming out the vent right outside the windshield, which is sectioned off from the engine. Is that where the blower motor vents? Maybe smoke would not come into the cabin?

 

[99WhiteC5Coupe]

It is strange as I only smell it when I am outside the car. Seems like it is coming out the vent right outside the windshield, which is sectioned off from the engine. Is that where the blower motor vents? Maybe smoke would not come into the cabin?

The blower motor doesn’t vent at the cowl, but rather draws in air from the base of the windshield (though the air inlet grille).

If the HVAC system is turned off, you may be smell the burning odor as it rises from the HVAC case, through the air inlet grille?

I would say it is unusual that if it is the HVAC system wiring or connectors, that you do not smell the odor inside the passenger compartment.

Have you raised the hood and examined the various wiring and connectors (not necessarily the HVAC wiring) near the engine cowl?

Have you examined the HVAC air filter to determine if it is clogged?

 

[apex96]

Burning could be the condenser clutch locking up. Had mine fail two years ago, similar smells.

Also as it gets cold and you auto start the vehicle. There are defrost strips under the wipers and they get hot enough to toast the wipers and also cause a faint burning rubber smell.

 

[spencerfrazier]

The blower motor doesn’t vent at the cowl, but rather draws in air from the base of the windshield (though the air inlet grille).

If the HVAC system is turned off, you may be smell the burning odor as it rises from the HVAC case, through the air inlet grille?

I would say it is unusual that if it is the HVAC system wiring or connectors, that you do not smell the odor inside the passenger compartment.

Have you raised the hood and examined the various wiring and connectors (not necessarily the HVAC wiring) near the engine cowl?

Have you examined the HVAC air filter to determine if it is clogged?

Thanks for the reply! I have checked the wiring/fuses all over under the hood. It doesn't seem like any burning smell is coming from anywhere near the engine. The first thing I did with the poor HVAC performance was to swap the HVAC filter. It wasn't too bad.