Air and heat problem
My car died recently. So I swapped battery's. Afterward, I realized my heat and ac in the front won't blow hard. Even if I put it on the highest level it still won't blow hard. Is this a blower motor or a blower motor resister problem?
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
You need to recalibrate the Mode Door Actuator. It lost track of it’s position during battery replacement.
Here are the steps for this:
Key off
Remove HVAC B fuse for 10 seconds
Install fuse
Start engine
Wait 1 minute for it to recalibrate without touching A/C controls
This should solve your issue. However, if you would like a technician to take care of this task for you, a certified technician from YourMechanic can come to your home or office to diagnose and repair your AC so that it will blow hard again.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common reasons a Chevrolet Trailblazer heater isn`t working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.
The most common reasons a Chevrolet Trailblazer is overheating are a coolant leak (water pump, radiator, hose etc.), the radiator fan, or a failed thermostat. Coolant leak (water pump, radiator, hose etc.)
Why does my Trailblazer`s engine overheat? There are two main causes for engine overheat: The coolant does not flow through the system like it should. There is not enough air flowing through the radiator.
LL8 (Vortec 4200)
It displaces 4.2 L; 253.9 cu in (4,160 cc), with a 93 mm × 102 mm (3.66 in × 4.02 in) bore and stroke. It has four valves per cylinder, utilizes dual-overhead cams (DOHC) design, and features variable valve timing on the exhaust cam, a first for GM inline engines.
If the heater isn`t blowing hot air at you when you turn the system on, the blower fan might have a problem. Either it`s not getting electrical power or, more likely, the motor itself has simply burned out. A blower motor in an older vehicle is likely to burn out over time, and may need replacement.
Keep an eye on engine temperature.
If your coolant level is a-okay, but your car heater is blowing cold air and your engine is overheating, then you have a clog in your cooling system. Conversely, if your engine temperatures are unrealistically low after a drive, your thermostat is likely the culprit.
The 4.2L straight-6 Vortec engine is extremely reliable. Worn valve seats are the only problem on our list that can lead to an expensive repair bill and the issue really isn`t common enough to give any worry. The fan clutch, water pump, sensors, end links, etc. are all very minor and inexpensive problems to fix.
The 4.2-liter Atlas LL8, otherwise called the Vortec 4200, was a groundbreaking engine for GM.
If you`re looking to buy an SUV with a Vortec 4200, we`re sure you won`t be disappointed. With many owners now running beyond 250,000 miles without significant issues, it`s a true testament to their reliability when correctly maintained.
A Clogged or Dirty Air Filter. If you find your furnace blowing cold air, you may have a dirty or clogged air filter. To make sure, remove the air filter and inspect it. If it`s clogged with dust, clean it with compressed air or wash it in warm water with mild soap or just buy a new one.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My heat and air turns on without a problem but does not blow very hard (heat blows harder than air). Rattling noise.
ANSWER : The heater and the air conditioner both use the same blower motor. However, Nissan does have two separate fuses for the same unit. One of them can be blown. There are also resistors in the system that can fail. There are several electrical tests that can be done, but depending on the condition, it may be more practice to change the entire unit. Due to the age of your vehicle, and the Juke’s history of blower motor issues, it’s very likely a simple fuse issue. These can (for the most part) be visually inspected, and are cheap.
A/C and heat are not working properly. Car blows heat in summer and cool air in winter.
ANSWER : Common causes of no cabin heat include malfunctioning blend door(s) (part of the in-dash ventilation network), a faulty or stuck heater control valve, a plugged heater core, stuck open engine cooling thermostat, collapsed hoses, and low coolant level. The cost to resolve the problem depends on which of the foregoing faults is the cause. If you desire a diagnostic to determine exactly why there is no cabin heat, please request a non functioning cabin heater diagnostic and the responding mechanic will come right to your location and get this resolved for you promptly.
With regard to your air conditioning system, if merely re-charging the system restored normal operation but the a/c ceased to function after a month or so, that scenario typically suggests a leak. Some leaks are really cheap to repair, like if a couple o-rings need to be replaced in system piping but if the leak is at the compressor shaft seal, that repair is more costly. It is not expensive to find the leak and diagnose the system and once the leak is found the mechanic can let you know of the exact cost to repair the leak and re-charge the system. If you desire that service please request an a/c system diagnostic – suspected refrigerant leak and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you
Air conditioning is blowing hot air – car stalls when A/C is on
ANSWER : In order to diagnose all the different problems you have, I having the A/C pressures checked to see if the system is low on refrigerant from a leaking compressor or another component. The rough idle may be due to a dirty throttle body and idle control system. If you would like to have this checked for you, a certified professional from YourMechanic can come to your car’s location to inspect the A/C and rough idle in order to proceed with the proper repairs.
Hot air mixed with cold blows from air conditioning
ANSWER : Hey there. You will most likely have to have a mechanic bypass the heater coolant lines to have this resolved. Your A/C may not be controlling the air flow inside the evaporator correctly out of the vents and may be the blend door actuator stuck in the heat position. Have the AC system diagnosed first before bypassing the heater.
Air conditioner blowing warm air. Heat blowing warm air. Neither hot or cold
ANSWER : If the A/C system is full and pressures are reading correctly, and the cooling system is in proper working order (thermostat opens, no overheating, etc.), then most likely the problem lies with the dash. The climate control head unit may be at fault. One or more blend doors behind the dash may be stuck or broken. If you’re unable to fix this issue yourself, consider YourMechanic, as one of our mobile technician can come diagnose the issue with your A/C firsthand and help you fix it accordingly.
Car will blow cold air but will not blow heat
ANSWER : The heater not working in some cases may be related to the overheating problem you are also having. This may be due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater core is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. When the cooling system is not properly circulating coolant through the motor, this results in the warm coolant not being pumped through the heater core properly in order to warm the inside of the vehicle.
Engine overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. As mentioned above, this also restricts the warm coolant from flowing through the heater core which uses this to blow warm air into the cab of the vehicle. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.
Cold mist/smoke like air comes out of the air vents when cold air is on.
ANSWER : If you are using regular outside air a/c instead of recirculated air you may be getting a large amount of outside air humidity and can cause a mist to come out of the a/c vents. You should make sure the a/c evaporator drain is cleared and drains freely or the water in the a/c cannot drain fast enough and the blower will pick up the water and blow it out the vents.
Vehicle at running temp, turn on heat, no heat – stomp on gas, there is heat – ??? 2004 Jeep Liberty
ANSWER : Hello – regarding your lack of heater function unless the engine is revved up a bit, you have a coolant flow issue. This could be caused by a worn water pump (engine might be running warmer than normal?), a partially blocked heater control valve (adjustment problem or failed heater control switch), or clogged cooling system that simply has poor flow. I would recommend an inspection of the heater & cooling system by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.
