HVAC vent selector switch isn’t working. Replaced selector cable. Still won’t switch.

My vent selector switch is stuck on defrost. I opened up the housing unit and turns out the switch cable was broken. I replaced that with a new working one and the switch still won't move. I'm guessing the actual lever is stuck or there is debris near one of the vent doors keeping it from moving. I haven't gone any further than replacing the cable unit though.

My car has 127000 miles.
My car has a manual transmission.

Experienced mechanics share their insights in answering this question :
Hello.

If replacing the cable did not fix the issue then the problem is likely rooted elsewhere. If the lever does not appear to be broken it may just be stuck and needs to be unjammed and lubricated. It may also be possible, as you have suggested, that debris is jamming the vents, causing the entire lever and cable assembly to be stuck. I would recommend disassembling the switch / lever assembly to see if it is perhaps jammed or broken and going from there. This may require disassembly of the vehicle’s interior in order to access the components. If you’d like assistance in diagnosing and repairing this issue, a certified YourMechanic technician can be dispatched to your location to perform a heating/AC inspection.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Here are some of the most common causes of why air doesn`t flow out of your vehicle`s vents: Your air intake is clogged, meaning that air isn`t getting in from the outside at all or isn`t circulating properly. There is a blown fuse in the ventilation system. Electrical issues such as a bad relay.
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.
It sounds like you have a problem with the vacuum supply to the HVAC control head. Engine vacuum is what changes the airflow to the vents and floor. Defrost is the default position when there is not a vacuum source.
If you are experiencing weak airflow from vents in the house, check whether it is happening only in one vent or multiple vents. In case only one vent shows the problem, you may be having a problem with a disconnected or leaky duct, a crushed duct flex or a closed damper.
The most common problems that cause a lack of airflow include frozen coils, broken fan and restricted airflow due to dirty air filters or vent obstruction. However, there are many other issues that can lead to minimal airflow, so it may be necessary to ask the professionals.
The blower motor is responsible for sending air through the vents of your car. Over time, blower motors can become damaged, or completely fail. In which case, air will no longer come out of your vents.
Mode Door Actuators: The mode door actuator controls what vents have air flow, i.e. floor, panel or front, defrost, or any combination of those. Recirculation Door Actuators: The recirculation door actuator controls the intake of air into the system, either bringing outside air in or using inside air in recirculation.
You`ll know the defrost cycle is activated when the heat pump switches from heating to cooling. You may hear the reversing valve when this occurs. Another sign the defrost cycle is running is the indoor unit will run but the outdoor fan will be off.
Blocked Vent or Duct

A reasonably simple explanation for poor airflow in a particular area of your house could be that you have a blockage in an air duct near that area. If the problem affects one room, the vent in that room could have some blockage.

The blower motor is responsible for sending air through the vents of your car. Over time, blower motors can become damaged, or completely fail. In which case, air will no longer come out of your vents.
The blower motor is responsible for sending air through the vents of your car. Over time, blower motors can become damaged, or completely fail. In which case, air will no longer come out of your vents.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

HVAC vent selector switch isn’t working. Replaced selector cable. Still won’t switch.
ANSWER : Hello.

If replacing the cable did not fix the issue then the problem is likely rooted elsewhere. If the lever does not appear to be broken it may just be stuck and needs to be unjammed and lubricated. It may also be possible, as you have suggested, that debris is jamming the vents, causing the entire lever and cable assembly to be stuck. I would recommend disassembling the switch / lever assembly to see if it is perhaps jammed or broken and going from there. This may require disassembly of the vehicle’s interior in order to access the components. If you’d like assistance in diagnosing and repairing this issue, a certified YourMechanic technician can be dispatched to your location to perform a heating/AC inspection.

Just replaced head gasket, changed crack sensor new plugs. The check engine light is on, but dim, the only other light that the dash is a normal battery indicator. The fuel pump is not running when switch is turned on, the power windows don’t work, it turns over but not firing. It’s like only one part of the system is working. Also the heater fans work even if the switch is off.
ANSWER : I would first look at the diagnostic trouble codes. Those codes are available because the check engine light is on. If the fuel pump is not running (momentarily) at key on, that fault alone will prevent the car from starting as there will be no fuel pressure. Pump output and pressure can be directly tested and you can also check for electrical power to the pump. To find out why the engine will not run, the recommended diagnostic is a no start diagnostic. If you request that service, 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.

Does graphite lube work well for the ignition switch cylinder? Will it still need to be replaced if it does work?
ANSWER : Graphite lube is a great trick to unstick ignitions and door locks. Sometimes, when the steering wheel locks, you will have a hard time turning the key. In the heat of the moment frustrations take over and we can get a little rough turning the key and damage can occur. I too have been a victim of this, especially when you’re running late.

If something is bound up inside the key cylinder, graphite is the first thing to try when attempting to unstick whatever is keeping the key from moving. Once free, they key should work without issue. In most cases, if they key cylinder has been freed, a replacement is not necessary. If a pattern starts to arise and this happens more, then it is likely a ignition key cylinder replacement may be needed.

For some peace of mind, try carrying some graphite lube in your glove box and in the first sign of a stuck key, gently wiggle the steering wheel and key at the same time in attempt to make the key turn successfully. If you want a second opinion on this, feel free to reach out to a certified mechanic who can diagnose your ignition system first hand and fix any issues accordingly.

EPC light on 2004 Jetta. Code said brake switch faulty, but brakes lights worked. Replaced brake switch, now no brake lights.
ANSWER : Hi there. The first thing that pops in my mind beyond of what you have listed is perhaps the electrical harness attached to the brake switch. Perhaps the harness itself is damaged or you have an exposed wire, loose ground wire somewhere. You might want to have a professional mobile mechanic come to your location and complete a brake lights not working inspection to help you diagnose this issue.

My dash board don’t work my front light work when I change my light into high beam and my back window won’t go down
ANSWER : As unfortunate as it is, your vehicle would be considered flood damaged. Diagnosing electrical problems in a flood damaged vehicle is nearly impossible. This would take many hours or even days to determine which wiring harnesses and circuits have been affected. Then nearly all of the wiring under the dash would likely require replacement as well as many sensors and switches. On a BMW vehicle, the amount of wires and switches are likely more than that of a lower end vehicle. Due to the inefficiency in cost, you would likely be able to purchase another BMW like yours for less than what it would cost to fix your car. Many insurance companies would consider this type of damage to total out the vehicle unfortuantely.

I replaced the tailight assembly but the the brake light still won’t turn on.
ANSWER : You will need to do some further testing to figure out where the issue is. This is going to require you trace the power supply from the brake pedal to the bulb. All of the following can be the cause and should be check out. Luckily the brake light circuit is not extremely complicated. The connection to the brake lights is most likely not being made. This can be do to the brake light sensor located at the brake pedal. It can be due to a short or wiring damage between the switch and the bulb. The issue may be the wiring terminal into the brake light assembly. It may be the bulb socket. Have you checked all related fuses? Using a voltmeter, you can test for available voltage across all of these components and find where the voltage drop occurs. That will be the component which has failed and needs to be replaced.

I just replaced the front passenger window regulator and motor and it works but only when i am using the rear passenger switch
ANSWER : Your Audi uses a window control module to operate the windows. The switches send a command to the module, and the module sends the power to the window motors. I’ve seen the modules do some screwy things, especially when the battery voltage gets low, but I wouldn’t run out and buy a module just yet. It may be possible to communicate with it with the right software and there might be some re-set that can be done. If you contact Your Mechanic, they can send a technician to your home or office to check out your spooky windows and tell you whether you need a new module or something else.

Won’t start. Replaced starter and relay switch, still won’t start. Tested battery and it’s good.
ANSWER : Hey there, thank you for asking about your 2001 Nissan Pathfinder. You should check fuse number 18 in the fuse panel under the dash. Test the black and yellow wire at the start interrupt relay to see if it gets power when you turn the key to start. If it does, then you are getting power from the ignition switch. Then check the black and pink wire at the relay to see if you get power when you try and crank the engine. If you get no power, then you may have a bad neutral start switch on the transmission. Try to move your transmission through gears and neutral while trying to crank it, holding the brake in case it starts. If you find it will start in one of the gears, then check the shift linkage. If it’s okay, replace the shift interrupt switch on the transmission. If you want to have this checked by a certified mechanic, a technician from YourMechanic can come to your home or office to inspect your starting problem.