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  • Writer's pictureCooper Maiks


Updated: Jan 31, 2021

You’re driving down the road on a sweltering Houston day with your vehicle’s air conditioner (AC) on, and suddenly it stops working or starts blowing hot air! There are several telltale indications that your air conditioning and/or heating unit may be having “issues”. Some of the most common are:

Smells Like Mildew

When you switch on your AC, the air smells like mildew. This is likely due to bacterial or fungal growth in the system, which is common with vehicles that seldom use their AC or frequently use the maximum setting (due to extra moisture in the unit). The growth produces a foul odor that comes out the vents.

Water on Floorboards

When bacteria start building up on the air conditioner’s evaporator in the AC/heater box (located under your dashboard), it mixes with the condensation from the coils. This leads to the development of a slimy film on the AC fins. When the film thickens over time, it can clog the drain line. Once plugged, water from the condensation fills up the AC/heater box and begins dripping out onto your vehicle’s floor, typically on the passenger side.

No Air From Vents

There are numerous possibilities in this case:

  • It could be either a blown fuse or bad relay. If the ventilation fuse blows or a relay goes out, there will be no power to the blower motor, thereby preventing air from blowing through the vents.

  • The blower motor or blower resistor might have suffered damage. The former is responsible for pushing air through the vents and can malfunction due to wear or age. The blower resistor assists the blower motor in controlling the level of air being produced to flow through vents, so any damage can interrupt smooth functioning of the A/C.

  • Blocked air intake due to a clogged filter or other debris. This means the vents might blow little to no-air.

  • Yet another reason is damaged belts and hoses. Any sort of leak, detachment, or blockages will prevent proper airflow from the vents.

Unit Produces Hot Air/Cool Air Rather Than COLD AIR

The issue might be due to a refrigerant leak. When refrigerant levels drop low it reduces pressure, which prevents the clutch from triggering the compressor to begin its cycle. Other reasons include a blocked or failed condenser, or failed clutch switch. When the air from the vents becomes incredibly hot, it is quite possible the expansion valve that dispenses the correct amount of refrigerant to the evaporator has failed.

The Unit Makes Noise When Turned On

When you hear rattling, banging, or other unusual sounds when the A/C is turned on, it could indicate leaves or other road debris is blocking the unit. It might be something more serious too, such as a major component failure.

CooperMaiks is your full service vehicle maintenance and repair facility located in Stafford. Please visit our website to learn more about the types of AC services and repairs offered.

You can also call 281-499-3922 or stop by our 235 Dulles Ave. location to set an appointment to have your vehicle’s AC evaluated.

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