One of the most inconvenient vehicular problems is when the A/C won’t blow cold air. If your Mercury Mountaineer isn’t keeping you cool, we’ve outlined some of the most common reasons why this might be happening.
It is entirely possible for your Mountaineer’s heater to work just fine even when the air conditioner is blowing hot air. That’s why troubleshooting the air conditioner is totally different than troubleshooting the heater.
Diagnostic Order
You’ll see below that there is a number of reasons why your Mountaineer’s AC may not be blowing cold. Here’s a good order to go about checking your vehicle’s air conditioning system:
- First, check the condenser to make sure it’s not blocked by any debris.
- Inspect the cabin air filter (if equipped) to verify that it is not clogged.
- Determine if the blend door is moving.
- Check the system pressure. If it’s low, you’ll need to charge it and find out where the leak came originated. Here’s how to test and determine if there is a leak.
- If there isn’t a leak, the blend door is working, and the system pressure is OK, you’ll likely need to replace the condenser, evaporator, fan, or compressor. There’s a section on each below.
Mercury Mountaineer Air Conditioning Not Blowing Cold: Causes
Here are the most common causes of an AC system not blowing cold in the Mercury Mountaineer:
Lack of Refrigerant
Your Mountaineer’s air conditioner will not work if the refrigerant level is too low. In fact, most compressors won’t even cycle on without the right amount of refrigerant pressure (this saves them from eating themselves).
A low refrigerant level is perhaps the most common reason that your Mountaineer’s air conditioner is not blowing cold. It can be tempting to get more coolant and get back on the road, but unless you find where the leak is coming from, it’ll eventually happen again.
Bad Condenser
An AC condenser is a little radiator that pulls the heat out of your vehicle’s refrigerant. Weak airflow to it will reduce its efficiency. Check the condenser to see if it’s blocked by debris.
If your condenser has taken damage or is clogged up, it can’t remove the heat from the refrigerant.
Check to ensure that the electric fan over the condenser is engaging. If the cooling system works better on the highway (where fans aren’t needed), your Mountaineer may be having fan issues (blown a fuse, bad motor, wiring harness damage).
Faulty Compressor
A faulty compressor will not move the refrigerant through the system properly. Here are the four main reasons why your Mountaineer’s may not be working:
- Clutch Cycling Switch– AC systems use an electromagnetic clutch to activate the compressor. When this switch fails, your air conditioning will only blow warm air.
- Slipping Belt- A slipping serpentine belt can cause the vehicle’s AC compressor to turn slower than it otherwise would, which will cause the AC system to not cool enough.
- Sitting For a Long Time– If your Mountaineer has been sitting for a long time, it can really be hard on the AC compressor.
- Wiring Issues– If there’s a blown fuse or compressor wiring issue, the air coming in should be equivalent to the outside temperature at best. The compressor won’t be working at all.
Dirty Cabin Air Filter
Most (but not all) modern vehicles come with a cabin air filter, and it’s one of the most neglected maintenance items.
When a cabin air filter gets dirty, airflow is reduced. If your blower motor is set on high and you don’t feel much airflow, this is likely the issue. However, it isn’t hard to change a cabin air filter.
Faulty Blower Motor
If there is no air blowing from your Mountaineer at all, the blower motor is at fault. The good news is, they are not that expensive and are easy to replace (most of the time).
Blend Door
The blend door controls how much air-conditioned and heated air enters the cabin. If it gets jammed or locks up, your Mountaineer can’t respond to your temperature change request.
Most modern blend doors are controlled by the computer via actuators. These actuators can go bad. If you hear the sound below, you may have a bad actuator.
Your vehicle’s blend door can freeze up after a long trip. For example, if you have run your Mountaineer for several hours, and the temperature won’t change when you adjust it, there’s a good chance the blend door froze up.
Conclusion: Mercury Mountaineer AC Not Blowing Cold
These are a few of the most common issues that could cause your Mountaineer not to blow cold enough. However, there are other issues that can cause this as well.
Most of the time, when your Mountaineer’s air isn’t blowing cold enough, it is going to be a lack of refrigerant causing the problem.
We recommend having a professional recharge your A/C and fix the leak if it does end up being a coolant issue. If you put too much coolant into the system, it can really do some damage.