Mercury Mariner Hybrid Problems

RepairPal has identified the most common problems with the Mercury Mariner Hybrid as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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5
Known Problems

The Mercury Mariner Hybrid equipped with automatic temperature control may have a problem with frequent fan speed changes when using the heater or air conditioner. Normally, the fan speed changes only to maintain a selected temperature, but when the fan speed changes frequently and needlessly, there is an issue with the fan speed control unit. 

The fan speed control unit, sometimes erroneously called the blower motor resister, regulates the speed for the blower motor in order to maintain the temperature set by the driver. When it fails, the fan will run at random settings, and the climate control will be inaccurate.

Note: this does not affect the temperature of the air that comes from the vents, it affects the amount of air that comes from the vents. 

The repair is simple, and quick. The control unit is located behind the glove box in most models, and removal and installation takes only minutes.

Also note: this only applies to vehicles with single or dual automatic climate control.

The 2008-2011 Mercury Mariner Hybrid with manual temperature and fan controls may have problems with the the blower motor only blowing air on certain settings. Most commonly the fan will only run on the highest setting. This is a well documented problem, and is caused by a failing blower motor resistor.

Correcting the problem is straight forward, and requires replacement of the small resistor. The resistor is normally found behind the glove box, next to the blower motor.

The hybrid models have a coolant pump that cools control electronics. The pump can fail or spin slowly, which causes a Check Engine Light to illuminate and complete engine shut down.

The Check Engine Light may illuminate with code P0442, P0456, and/or P1450. These codes are related to the EVAP system. Our technicians tell us that if no EVAP system faults are confirmed, updated software is available for the powertrain control module (PCM) which should correct this concern.

Hard driving conditions, including quick starts from a stop and hard acceleration up hills, can cause the rear motor mount to crack. The broken motor mount needs to be replaced, otherwise damage to the hybrid drive system may result.